CVE-2024-49940

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2024-49940", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-10-21T12:17:06.043Z", "datePublished": "2024-10-21T18:01:59.668Z", "dateUpdated": "2026-10-30T12:19:44.806Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-30T12:19:44.806Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nl2tp: prevent possible tunnel refcount underflow\n\nWhen a session is created, it sets a backpointer to its tunnel. When\nthe session refcount drops to 0, l2tp_session_free drops the tunnel\nrefcount if session->tunnel is non-NULL. However, session->tunnel is\nset in l2tp_session_create, before the tunnel refcount is incremented\nby l2tp_session_register, which leaves a small window where\nsession->tunnel is non-NULL when the tunnel refcount hasn't been\nbumped.\n\nMoving the assignment to l2tp_session_register is trivial but\nl2tp_session_create calls l2tp_session_set_header_len which uses\nsession->tunnel to get the tunnel's encap. Add an encap arg to\nl2tp_session_set_header_len to avoid using session->tunnel.\n\nIf l2tpv3 sessions have colliding IDs, it is possible for\nl2tp_v3_session_get to race with l2tp_session_register and fetch a\nsession which doesn't yet have session->tunnel set. Add a check for\nthis case."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - The refcount underflow is triggered by local session creation \u2014 either the L2TP generic-netlink `L2TP_CMD_SESSION_CREATE` command or a `connect()` on an `AF_PPPOX`/`PX_PROTO_OL2TP` socket. A remote peer cannot itself drive `l2tp_session_create()`/`l2tp_session_register()`, though remote packets in `l2tp_udp_encap_recv()` are what subsequently dereference the prematurely freed tunnel.\nAC:L - The attacker fully controls both sides: they choose the session ID, so they can deterministically force `l2tp_session_register()` to fail (`-EEXIST` on a colliding L2TPv3 ID, or `-ENODEV`), and they can run concurrent create/teardown threads to widen the window between `l2tp_session_create()` and the tunnel refcount bump. No condition outside attacker influence is required, and L2TP is a stock distro module.\nPR:L - `pppol2tp_create()`/`pppox_create()` perform no capability check, so a plain unprivileged local user can reach `l2tp_session_create()` and `l2tp_session_register()` through `connect()`. The netlink path is `GENL_UNS_ADMIN_PERM` (CAP_NET_ADMIN against the netns user_ns), which any unprivileged user obtains via `unshare -Urn`.\nUI:N - The attacker performs the entire sequence \u2014 tunnel setup, session creation with a colliding ID, and session teardown \u2014 from their own process. No victim action or cooperating user is involved.\nS:U - The underflow and the resulting use-after-free are confined to the kernel's own l2tp objects within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The dropped-too-early tunnel reference frees `struct l2tp_tunnel` while `session->tunnel` and the datapath still reference it, giving a use-after-free on a kmalloc'd object that can be reclaimed with attacker-sprayed data and then read back (e.g. `tunnel->sock`, `tunnel->encap`, `tunnel->version` used in `l2tp_recv_common()`/`l2tp_xmit_skb()`), enabling kernel memory disclosure.\nI:H - A use-after-free on the tunnel object lets an attacker reoccupy the freed slab and control fields such as `tunnel->sock`, which the transmit and receive paths dereference and pass to socket operations, yielding a write/control-flow-hijack primitive. Additionally the extra `l2tp_tunnel_dec_refcount()` corrupts kernel reference-counting state itself.\nA:H - Premature tunnel free reliably produces an oops/panic when the still-live session or a received L2TP packet dereferences the dangling `session->tunnel`, and the `refcount_t` underflow itself raises a WARN that panics on `panic_on_warn` systems."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/l2tp/l2tp_core.c", "net/l2tp/l2tp_core.h", "net/l2tp/l2tp_netlink.c", "net/l2tp/l2tp_ppp.c"], "versions": [{"version": "3953ae7b218df4d1e544b98a393666f9ae58a78c", "lessThan": "aa7132362e79abc4f2add4d8657dd1679341edc5", "status": "affected", "versionType": "git"}, {"version": "3953ae7b218df4d1e544b98a393666f9ae58a78c", "lessThan": "98691b2e28a6c3dac0680914493d54c77f215755", "status": "affected", "versionType": "git"}, {"version": "3953ae7b218df4d1e544b98a393666f9ae58a78c", "lessThan": "f7415e60c25a6108cd7955a20b2e66b6251ffe02", "status": "affected", "versionType": "git"}, {"version": "3953ae7b218df4d1e544b98a393666f9ae58a78c", "lessThan": "24256415d18695b46da06c93135f5b51c548b950", "status": "affected", "versionType": "git"}, {"version": "b102bfc2a90d14f342580285782a9a51c74f7369", "status": "affected", "versionType": "git"}, {"version": "10c15ddabbcf888922adbdd44ca3fecf6eab19d9", "status": "affected", "versionType": "git"}, {"version": "8d1c650d452c53fcb3f02a7b1d772741639f89a4", "status": "affected", "versionType": "git"}, {"version": "12b5fb58ac993c24210cf8cbc72d407d3a4e6490", "status": "affected", "versionType": "git"}, {"version": "aef37401b467a0b1a9517c69924a1d66937e0789", "status": "affected", "versionType": "git"}, {"version": "3.2.99", "lessThan": "3.3", "status": "affected", "versionType": "semver"}, {"version": "3.16.54", "lessThan": "3.17", "status": "affected", "versionType": "semver"}, {"version": "4.4.225", "lessThan": "4.5", "status": "affected", "versionType": "semver"}, {"version": "4.9.225", "lessThan": "4.10", "status": "affected", "versionType": "semver"}, {"version": "4.14.182", "lessThan": "4.15", "status": "affected", "versionType": "semver"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/l2tp/l2tp_core.c", "net/l2tp/l2tp_core.h", "net/l2tp/l2tp_netlink.c", "net/l2tp/l2tp_ppp.c"], "versions": [{"version": "4.15", "status": "affected"}, {"version": "0", "lessThan": "4.15", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.191", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.11.3", "lessThanOrEqual": "6.11.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "6.1.191"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "6.6.160"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "6.11.3"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "6.12"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2.99"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.16.54"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.4.225"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9.225"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14.182"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/aa7132362e79abc4f2add4d8657dd1679341edc5"}, {"url": "https://git.kernel.org/stable/c/98691b2e28a6c3dac0680914493d54c77f215755"}, {"url": "https://git.kernel.org/stable/c/f7415e60c25a6108cd7955a20b2e66b6251ffe02"}, {"url": "https://git.kernel.org/stable/c/24256415d18695b46da06c93135f5b51c548b950"}], "title": "l2tp: prevent possible tunnel refcount underflow", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2024-49940", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2024-10-22T13:37:52.827630Z"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-10-22T13:38:50.656Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2024-49940", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2024-10-22T13:37:52.827630Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-10-22T13:37:56.128Z"}}], "cna": {"title": "l2tp: prevent possible tunnel refcount underflow", "metrics": [{"cvssV3_1": {"version": "3.1", "baseScore": 7.8, "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}, "scenarios": [{"lang": "en", "value": "AV:L - The refcount underflow is triggered by local session creation \u2014 either the L2TP generic-netlink `L2TP_CMD_SESSION_CREATE` command or a `connect()` on an `AF_PPPOX`/`PX_PROTO_OL2TP` socket. A remote peer cannot itself drive `l2tp_session_create()`/`l2tp_session_register()`, though remote packets in `l2tp_udp_encap_recv()` are what subsequently dereference the prematurely freed tunnel.\nAC:L - The attacker fully controls both sides: they choose the session ID, so they can deterministically force `l2tp_session_register()` to fail (`-EEXIST` on a colliding L2TPv3 ID, or `-ENODEV`), and they can run concurrent create/teardown threads to widen the window between `l2tp_session_create()` and the tunnel refcount bump. No condition outside attacker influence is required, and L2TP is a stock distro module.\nPR:L - `pppol2tp_create()`/`pppox_create()` perform no capability check, so a plain unprivileged local user can reach `l2tp_session_create()` and `l2tp_session_register()` through `connect()`. The netlink path is `GENL_UNS_ADMIN_PERM` (CAP_NET_ADMIN against the netns user_ns), which any unprivileged user obtains via `unshare -Urn`.\nUI:N - The attacker performs the entire sequence \u2014 tunnel setup, session creation with a colliding ID, and session teardown \u2014 from their own process. No victim action or cooperating user is involved.\nS:U - The underflow and the resulting use-after-free are confined to the kernel's own l2tp objects within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The dropped-too-early tunnel reference frees `struct l2tp_tunnel` while `session->tunnel` and the datapath still reference it, giving a use-after-free on a kmalloc'd object that can be reclaimed with attacker-sprayed data and then read back (e.g. `tunnel->sock`, `tunnel->encap`, `tunnel->version` used in `l2tp_recv_common()`/`l2tp_xmit_skb()`), enabling kernel memory disclosure.\nI:H - A use-after-free on the tunnel object lets an attacker reoccupy the freed slab and control fields such as `tunnel->sock`, which the transmit and receive paths dereference and pass to socket operations, yielding a write/control-flow-hijack primitive. Additionally the extra `l2tp_tunnel_dec_refcount()` corrupts kernel reference-counting state itself.\nA:H - Premature tunnel free reliably produces an oops/panic when the still-live session or a received L2TP packet dereferences the dangling `session->tunnel`, and the `refcount_t` underflow itself raises a WARN that panics on `panic_on_warn` systems."}]}], "affected": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "3953ae7b218df4d1e544b98a393666f9ae58a78c", "lessThan": "aa7132362e79abc4f2add4d8657dd1679341edc5", "versionType": "git"}, {"status": "affected", "version": "3953ae7b218df4d1e544b98a393666f9ae58a78c", "lessThan": "98691b2e28a6c3dac0680914493d54c77f215755", "versionType": "git"}, {"status": "affected", "version": "3953ae7b218df4d1e544b98a393666f9ae58a78c", "lessThan": "f7415e60c25a6108cd7955a20b2e66b6251ffe02", "versionType": "git"}, {"status": "affected", "version": "3953ae7b218df4d1e544b98a393666f9ae58a78c", "lessThan": "24256415d18695b46da06c93135f5b51c548b950", "versionType": "git"}, {"status": "affected", "version": "b102bfc2a90d14f342580285782a9a51c74f7369", "versionType": "git"}, {"status": "affected", "version": "10c15ddabbcf888922adbdd44ca3fecf6eab19d9", "versionType": "git"}, {"status": "affected", "version": "8d1c650d452c53fcb3f02a7b1d772741639f89a4", "versionType": "git"}, {"status": "affected", "version": "12b5fb58ac993c24210cf8cbc72d407d3a4e6490", "versionType": "git"}, {"status": "affected", "version": "aef37401b467a0b1a9517c69924a1d66937e0789", "versionType": "git"}, {"status": "affected", "version": "3.2.99", "lessThan": "3.3", "versionType": "semver"}, {"status": "affected", "version": "3.16.54", "lessThan": "3.17", "versionType": "semver"}, {"status": "affected", "version": "4.4.225", "lessThan": "4.5", "versionType": "semver"}, {"status": "affected", "version": "4.9.225", "lessThan": "4.10", "versionType": "semver"}, {"status": "affected", "version": "4.14.182", "lessThan": "4.15", "versionType": "semver"}], "programFiles": ["net/l2tp/l2tp_core.c", "net/l2tp/l2tp_core.h", "net/l2tp/l2tp_netlink.c", "net/l2tp/l2tp_ppp.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "4.15"}, {"status": "unaffected", "version": "0", "lessThan": "4.15", "versionType": "semver"}, {"status": "unaffected", "version": "6.1.191", "versionType": "semver", "lessThanOrEqual": "6.1.*"}, {"status": "unaffected", "version": "6.6.160", "versionType": "semver", "lessThanOrEqual": "6.6.*"}, {"status": "unaffected", "version": "6.11.3", "versionType": "semver", "lessThanOrEqual": "6.11.*"}, {"status": "unaffected", "version": "6.12", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["net/l2tp/l2tp_core.c", "net/l2tp/l2tp_core.h", "net/l2tp/l2tp_netlink.c", "net/l2tp/l2tp_ppp.c"], "defaultStatus": "affected"}], "references": [{"url": "https://git.kernel.org/stable/c/aa7132362e79abc4f2add4d8657dd1679341edc5"}, {"url": "https://git.kernel.org/stable/c/98691b2e28a6c3dac0680914493d54c77f215755"}, {"url": "https://git.kernel.org/stable/c/f7415e60c25a6108cd7955a20b2e66b6251ffe02"}, {"url": "https://git.kernel.org/stable/c/24256415d18695b46da06c93135f5b51c548b950"}], "x_generator": {"engine": "bippy-1.2.0"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nl2tp: prevent possible tunnel refcount underflow\n\nWhen a session is created, it sets a backpointer to its tunnel. When\nthe session refcount drops to 0, l2tp_session_free drops the tunnel\nrefcount if session->tunnel is non-NULL. However, session->tunnel is\nset in l2tp_session_create, before the tunnel refcount is incremented\nby l2tp_session_register, which leaves a small window where\nsession->tunnel is non-NULL when the tunnel refcount hasn't been\nbumped.\n\nMoving the assignment to l2tp_session_register is trivial but\nl2tp_session_create calls l2tp_session_set_header_len which uses\nsession->tunnel to get the tunnel's encap. Add an encap arg to\nl2tp_session_set_header_len to avoid using session->tunnel.\n\nIf l2tpv3 sessions have colliding IDs, it is possible for\nl2tp_v3_session_get to race with l2tp_session_register and fetch a\nsession which doesn't yet have session->tunnel set. Add a check for\nthis case."}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.1.191", "versionStartIncluding": "4.15"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.6.160", "versionStartIncluding": "4.15"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.11.3", "versionStartIncluding": "4.15"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.12", "versionStartIncluding": "4.15"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionStartIncluding": "3.2.99"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionStartIncluding": "3.16.54"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionStartIncluding": "4.4.225"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionStartIncluding": "4.9.225"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionStartIncluding": "4.14.182"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-30T12:19:44.806Z"}}}, "cveMetadata": {"cveId": "CVE-2024-49940", "state": "PUBLISHED", "dateUpdated": "2026-10-30T12:19:44.806Z", "dateReserved": "2024-10-21T12:17:06.043Z", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "datePublished": "2024-10-21T18:01:59.668Z", "assignerShortName": "Linux"}, "dataVersion": "5.2"}

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When\nthe session refcount drops to 0, l2tp_session_free drops the tunnel\nrefcount if session->tunnel is non-NULL. However, session->tunnel is\nset in l2tp_session_create, before the tunnel refcount is incremented\nby l2tp_session_register, which leaves a small window where\nsession->tunnel is non-NULL when the tunnel refcount hasn't been\nbumped.\n\nMoving the assignment to l2tp_session_register is trivial but\nl2tp_session_create calls l2tp_session_set_header_len which uses\nsession->tunnel to get the tunnel's encap. Add an encap arg to\nl2tp_session_set_header_len to avoid using session->tunnel.\n\nIf l2tpv3 sessions have colliding IDs, it is possible for\nl2tp_v3_session_get to race with l2tp_session_register and fetch a\nsession which doesn't yet have session->tunnel set. Add a check for\nthis case."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: l2tp: evitar un posible desbordamiento del recuento de referencias del t\u00fanel Cuando se crea una sesi\u00f3n, establece un puntero hacia atr\u00e1s a su t\u00fanel. Cuando el recuento de referencias de la sesi\u00f3n cae a 0, l2tp_session_free descarta el recuento de referencias del t\u00fanel si session->tunnel no es NULL. Sin embargo, session->tunnel se establece en l2tp_session_create, antes de que el recuento de referencias del t\u00fanel se incremente mediante l2tp_session_register, lo que deja una peque\u00f1a ventana donde session->tunnel no es NULL cuando el recuento de referencias del t\u00fanel no se ha incrementado. Mover la asignaci\u00f3n a l2tp_session_register es trivial, pero l2tp_session_create llama a l2tp_session_set_header_len, que usa session->tunnel para obtener el encap del t\u00fanel. Agregue un argumento de encap a l2tp_session_set_header_len para evitar usar session->tunnel. Si las sesiones l2tpv3 tienen identificadores en conflicto, es posible que l2tp_v3_session_get compita con l2tp_session_register y obtenga una sesi\u00f3n que a\u00fan no tenga configurado session->tunnel. Agregue una verificaci\u00f3n para este caso."}], "id": "CVE-2024-49940", "lastModified": "2026-10-30T13:17:39.873", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 5.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2024-49940", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2024-10-22T13:37:52.827630Z", "version": "2.0.3"}}]}, "published": "2024-10-21T18:15:15.703", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/24256415d18695b46da06c93135f5b51c548b950"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/98691b2e28a6c3dac0680914493d54c77f215755"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/aa7132362e79abc4f2add4d8657dd1679341edc5"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/f7415e60c25a6108cd7955a20b2e66b6251ffe02"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "NVD-CWE-noinfo"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: l2tp: prevent possible tunnel refcount underflow", "id": "2320467", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2320467"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-672", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nl2tp: prevent possible tunnel refcount underflow\nWhen a session is created, it sets a backpointer to its tunnel. When\nthe session refcount drops to 0, l2tp_session_free drops the tunnel\nrefcount if session->tunnel is non-NULL. However, session->tunnel is\nset in l2tp_session_create, before the tunnel refcount is incremented\nby l2tp_session_register, which leaves a small window where\nsession->tunnel is non-NULL when the tunnel refcount hasn't been\nbumped.\nMoving the assignment to l2tp_session_register is trivial but\nl2tp_session_create calls l2tp_session_set_header_len which uses\nsession->tunnel to get the tunnel's encap. Add an encap arg to\nl2tp_session_set_header_len to avoid using session->tunnel.\nIf l2tpv3 sessions have colliding IDs, it is possible for\nl2tp_v3_session_get to race with l2tp_session_register and fetch a\nsession which doesn't yet have session->tunnel set. Add a check for\nthis case."], "name": "CVE-2024-49940", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Out of support scope", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Will not fix", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Will not fix", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Will not fix", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Will not fix", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2024-10-21T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2024-49940\nhttps://nvd.nist.gov/vuln/detail/CVE-2024-49940\nhttps://lore.kernel.org/linux-cve-announce/2024102127-CVE-2024-49940-1c88@gregkh/T"], "threat_severity": "Moderate"}

{}