CVE-2026-74727

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-74727", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.929Z", "datePublished": "2026-08-22T15:33:17.773Z", "dateUpdated": "2026-08-25T05:42:08.380Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-25T05:42:08.380Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\novpn: skip rehash for peers already removed from by_id\n\novpn_nl_peer_set_doit() resolves the target peer via\novpn_peer_get_by_id() before taking ovpn->lock. In the window between\nthe lookup (which only takes a refcount) and the subsequent\nspin_lock_bh(&ovpn->lock), a concurrent OVPN_CMD_PEER_DEL, keepalive\nexpiry, or socket teardown can take ovpn->lock first, run\novpn_peer_remove() to unhash the peer from all four tables (by_id,\nby_vpn_addr4/6, by_transp_addr) and release the lock. set_doit then\nacquires ovpn->lock and calls ovpn_peer_hash_vpn_ip(), which\nre-inserts the now-removed peer back into the rehashing tables.\n\nThe same race affects the float path: ovpn_peer_endpoints_update()\nholds only a refcount and acquires ovpn->lock very late (after async\nAEAD decrypt and a netlink notification), then rehashes the peer\nin the by_transp_addr table.\n\nThe resurrected peer becomes reachable again from the RX lookup\n(ovpn_peer_get_by_transp_addr) and the TX VPN-IP lookup, even though\nuserspace believes it is gone. Once the data-path refcount drops the\npeer is freed via call_rcu while the hash entries embedded in it\nremain linked, opening a UAF window.\n\nBail out of the rehash when hash_entry_id is unhashed, mirroring\nthe sentinel already used by ovpn_peer_remove() to detect the\nalready-removed state. The check is safe under ovpn->lock, which\nserializes every mutation of hash_entry_id, and is a no-op for the\nadd path because ovpn_peer_add_mp() inserts hash_entry_id before\ncalling ovpn_peer_hash_vpn_ip()."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL"}, "scenarios": [{"lang": "en", "value": "AV:N - The float-path UAF is reached from ovpn_udp_encap_recv()/ovpn_tcp_rcv() through ovpn_recv(), async AEAD decrypt, and ovpn_peer_endpoints_update(); a remote peer sends authenticated DATA_V2 packets over UDP/TCP to an internet-facing MP-mode OpenVPN gateway.\nAC:L - The remote peer controls float timing (new transport source), packet rate, and concurrent removal via TCP disconnect, UDP socket teardown, or keepalive expiry; netlink PEER_SET vs PEER_DEL races are likewise attacker-synchronized with no luck-dependent layout.\nPR:N - On an internet-facing MP-mode gateway, exploitation needs no Linux credentials on the victim\u2014only an established kernel-installed peer with valid AEAD keys (or namespace CAP_NET_ADMIN for netlink races), matching a remote VPN client rather than host root.\nUI:N - The rehash race is triggered by normal peer traffic and automatic keepalive/socket teardown; no administrator or end-user action on the victim host is required beyond routine VPN server operation.\nS:U - The UAF corrupts ovpn peer hash tables inside the kernel VPN driver; impact remains within the host kernel security domain without crossing VM, container, or IOMMU boundaries.\nC:H - Freed ovpn_peer objects remain linked in by_transp_addr/by_vpn_addr hash tables, so RX/TX lookups dereference recycled kmalloc-1k structures and enable arbitrary kernel-memory reads via attacker-controlled heap reuse.\nI:H - Resurrected hash entries steer traffic to freed peers and subsequent RCU/kref teardown on stale objects provide typical slab-UAF write primitives (refcount, socket, crypto pointer updates) suitable for kernel code execution.\nA:H - Use-after-free on hot datapath peer lookups reliably causes kernel oops/panic or slab corruption on VPN gateways, and remote peers can repeat the race to sustain denial of service."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/net/ovpn/peer.c"], "versions": [{"version": "1d36a36f6d5347360ef9681a05f6166683bafd1d", "lessThan": "d20c181088984b6eaa8d7fe7cb5ab3510988df59", "status": "affected", "versionType": "git"}, {"version": "1d36a36f6d5347360ef9681a05f6166683bafd1d", "lessThan": "66745480298775f188b2f5ad266643e85a90f73b", "status": "affected", "versionType": "git"}, {"version": "1d36a36f6d5347360ef9681a05f6166683bafd1d", "lessThan": "33ec10567fe14456063daf549fdf1a4f53448e4c", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/net/ovpn/peer.c"], "versions": [{"version": "6.16", "status": "affected"}, {"version": "0", "lessThan": "6.16", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.45", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.9", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2", "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": "6.16", "versionEndExcluding": "6.18.45"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "7.1.9"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "7.2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/d20c181088984b6eaa8d7fe7cb5ab3510988df59"}, {"url": "https://git.kernel.org/stable/c/66745480298775f188b2f5ad266643e85a90f73b"}, {"url": "https://git.kernel.org/stable/c/33ec10567fe14456063daf549fdf1a4f53448e4c"}], "title": "ovpn: skip rehash for peers already removed from by_id", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["drivers/net/ovpn/peer.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "d20c181088984b6eaa8d7fe7cb5ab3510988df59", "status": "affected", "version": "1d36a36f6d5347360ef9681a05f6166683bafd1d", "versionType": "git"}, {"lessThan": "66745480298775f188b2f5ad266643e85a90f73b", "status": "affected", "version": "1d36a36f6d5347360ef9681a05f6166683bafd1d", "versionType": "git"}, {"lessThan": "33ec10567fe14456063daf549fdf1a4f53448e4c", "status": "affected", "version": "1d36a36f6d5347360ef9681a05f6166683bafd1d", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["drivers/net/ovpn/peer.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.16"}, {"lessThan": "6.16", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.45", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.9", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\novpn: skip rehash for peers already removed from by_id\n\novpn_nl_peer_set_doit() resolves the target peer via\novpn_peer_get_by_id() before taking ovpn->lock. In the window between\nthe lookup (which only takes a refcount) and the subsequent\nspin_lock_bh(&ovpn->lock), a concurrent OVPN_CMD_PEER_DEL, keepalive\nexpiry, or socket teardown can take ovpn->lock first, run\novpn_peer_remove() to unhash the peer from all four tables (by_id,\nby_vpn_addr4/6, by_transp_addr) and release the lock. set_doit then\nacquires ovpn->lock and calls ovpn_peer_hash_vpn_ip(), which\nre-inserts the now-removed peer back into the rehashing tables.\n\nThe same race affects the float path: ovpn_peer_endpoints_update()\nholds only a refcount and acquires ovpn->lock very late (after async\nAEAD decrypt and a netlink notification), then rehashes the peer\nin the by_transp_addr table.\n\nThe resurrected peer becomes reachable again from the RX lookup\n(ovpn_peer_get_by_transp_addr) and the TX VPN-IP lookup, even though\nuserspace believes it is gone. Once the data-path refcount drops the\npeer is freed via call_rcu while the hash entries embedded in it\nremain linked, opening a UAF window.\n\nBail out of the rehash when hash_entry_id is unhashed, mirroring\nthe sentinel already used by ovpn_peer_remove() to detect the\nalready-removed state. The check is safe under ovpn->lock, which\nserializes every mutation of hash_entry_id, and is a no-op for the\nadd path because ovpn_peer_add_mp() inserts hash_entry_id before\ncalling ovpn_peer_hash_vpn_ip()."}, {"lang": "es", "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\novpn: omitir el rehash para pares ya eliminados de by_id\n\novpn_nl_peer_set_doit() resuelve el par objetivo a trav\u00e9s de ovpn_peer_get_by_id() antes de tomar ovpn -> lock. En la ventana entre la b\u00fasqueda (que solo toma un refcount) y el subsiguiente spin_lock_bh(&ovpn -> lock), un OVPN_CMD_PEER_DEL concurrente, la expiraci\u00f3n de un keepalive o el cierre de un socket pueden tomar ovpn -> lock primero, ejecutar ovpn_peer_remove() para deshashear el par de las cuatro tablas (by_id, by_vpn_addr4/6, by_transp_addr) y liberar el bloqueo. set_doit luego adquiere ovpn -> lock y llama a ovpn_peer_hash_vpn_ip(), lo que reinserta el par ahora eliminado de nuevo en las tablas de rehashing.\n\nLa misma condici\u00f3n de carrera afecta la ruta flotante: ovpn_peer_endpoints_update() solo mantiene un refcount y adquiere ovpn -> lock muy tarde (despu\u00e9s de un descifrado AEAD as\u00edncrono y una notificaci\u00f3n netlink), luego rehashea el par en la tabla by_transp_addr.\n\nEl par resucitado vuelve a ser accesible desde la b\u00fasqueda RX (ovpn_peer_get_by_transp_addr) y la b\u00fasqueda TX VPN-IP, aunque el userspace cree que ha desaparecido. Una vez que el refcount de la ruta de datos disminuye, el par es liberado a trav\u00e9s de call_rcu mientras que las entradas de hash incrustadas en \u00e9l permanecen vinculadas, abriendo una ventana UAF.\n\nSalir del rehash cuando hash_entry_id es deshasheado, reflejando el centinela ya utilizado por ovpn_peer_remove() para detectar el estado ya eliminado. La verificaci\u00f3n es segura bajo ovpn -> lock, que serializa cada mutaci\u00f3n de hash_entry_id, y es una operaci\u00f3n nula para la ruta de adici\u00f3n porque ovpn_peer_add_mp() inserta hash_entry_id antes de llamar a ovpn_peer_hash_vpn_ip()."}], "id": "CVE-2026-74727", "lastModified": "2026-10-14T13:10:00.187", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-08-22T16:16:47.813", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/33ec10567fe14456063daf549fdf1a4f53448e4c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/66745480298775f188b2f5ad266643e85a90f73b"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d20c181088984b6eaa8d7fe7cb5ab3510988df59"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: ovpn: skip rehash for peers already removed from by_id", "id": "2521379", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2521379"}, "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-825", "details": ["A flaw was found in the Linux kernel's ovpn module. A race condition can occur when an OpenVPN (ovpn) peer is removed concurrently while the system attempts to rehash it. This can lead to the peer being re-inserted into internal tables after it has been logically removed, creating a Use-After-Free (UAF) vulnerability. This flaw could allow an attacker to cause a denial of service or potentially execute arbitrary code."], "name": "CVE-2026-74727", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"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": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-08-22T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-74727\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-74727\nhttps://lore.kernel.org/linux-cve-announce/2026082241-CVE-2026-74727-bf4e@gregkh/T"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[1d36a36f6d5347360ef9681a05f6166683bafd1d,d20c181088984b6e7aa8d7fe7cb5ab3510988df59)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[1d36a36f6d5347360ef9681a05f6166683bafd1d,66745480298775f188b2f5ad266643e85a90f73b)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[1d36a36f6d5347360ef9681a05f6166683bafd1d,33ec10567fe14456063daf549fdf1a4f53448e4c)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "6.16"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.16)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.45,7.0.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.1.9,7.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-08-22T18:30:16.836741+00:00", "updated": "2026-08-25T10:00:09.629494+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}