CVE-2026-74434

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-74434", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.896Z", "datePublished": "2026-08-15T05:59:33.438Z", "dateUpdated": "2026-08-17T05:47:08.797Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:47:08.797Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: Don't move a peeked OOB message onto the pending queue\n\nrxrpc_recvmsg_oob() takes a received oob message off recvmsg_oobq and,\nif a response is needed, moves it onto the pending_oobq tree. However,\nonly the unlink from recvmsg_oobq is guarded by MSG_PEEK; the move onto\npending_oobq always runs.\n\nAs a result, reading a challenge with MSG_PEEK leaves the skb on\nrecvmsg_oobq while also adding it to pending_oobq. Since struct\nsk_buff's rbnode shares storage with its next and prev pointers,\nrb_insert_color() overwrites the list linkage, and the skb, which holds\na single reference, becomes reachable from both queues at once.\n\nWhen the socket is closed both queues are drained in turn. While\ndraining recvmsg_oobq, __skb_unlink() follows the next and prev\npointers that rbnode has overwritten and writes to a bad address. Also,\nas the skb holds a single reference but is freed from each queue, both\nthe skb and the connection reference it holds are released twice. This\nleads to memory corruption and to a use-after-free caused by the\nconnection refcount underflow.\n\nMSG_PEEK does not consume the message from the queue, so only unlink it\nfrom recvmsg_oobq and then move it onto pending_oobq or free it when\nthe message is actually consumed."}], "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 - A remote RxRPC/AFS peer can deliver CHALLENGE packets over UDP to a victim AF_RXRPC client socket; those packets are queued for recvmsg() handling, so the vulnerable rxrpc_recvmsg_oob() path is reached from network-driven authentication traffic rather than purely local-only APIs.\nAC:L - An attacker who controls both ends of the connection (or a malicious remote server and a userspace client) can reliably queue a CHALLENGE, call recvmsg(MSG_PEEK) with RXRPC_MANAGE_RESPONSE enabled, then close the socket to trigger duplicate queueing and deterministic double-free/UAF during OOB queue purge.\nPR:N - Exploitation requires no privileges on the victim host beyond what any unauthenticated remote RxRPC/AFS server already has to send protocol packets during connection security negotiation; no CAP_NET_ADMIN, root, or namespace-admin capability is needed on the target system.\nUI:N - No victim user interaction is required beyond normal automated RxRPC/AFS client operation that receives and processes authentication challenges from a server; the attacker does not need the victim to perform a separate manual action beyond routine client-server communication.\nS:U - The corrupted component is kernel RxRPC socket state and the impact is kernel memory corruption and privilege escalation within the same kernel security authority, not a cross-boundary escape such as a VM or sandbox breakout.\nC:H - The bug leaves one sk_buff referenced from both recvmsg_oobq and pending_oobq, causing double free and rxrpc_connection refcount underflow; this is a use-after-free/memory-corruption primitive that can expose or read freed kernel heap contents.\nI:H - rb_insert_color() overwrites sk_buff list linkage shared with rbnode, and socket teardown calls __skb_unlink() on corrupted pointers leading to out-of-bounds writes, enabling control of freed objects and potential arbitrary kernel code execution.\nA:H - Closing the socket drains both OOB queues and reliably triggers invalid pointer writes, skb double-free, and connection refcount underflow, producing kernel oops/panic and complete loss of system availability even without full exploitation."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/rxrpc/recvmsg.c"], "versions": [{"version": "5800b1cf3fd8ccab752a101865be1e76dac33142", "lessThan": "9ada3931beb37068fcb725b34b0398457009f343", "status": "affected", "versionType": "git"}, {"version": "5800b1cf3fd8ccab752a101865be1e76dac33142", "lessThan": "5f470cc883416fea6d3bce18ef96bf91dd49ffc3", "status": "affected", "versionType": "git"}, {"version": "5800b1cf3fd8ccab752a101865be1e76dac33142", "lessThan": "5801cff7d5d7b4e9d877dfb627b23eb63167f02c", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/rxrpc/recvmsg.c"], "versions": [{"version": "6.16", "status": "affected"}, {"version": "0", "lessThan": "6.16", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.5", "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": "6.18.40"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "7.1.5"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "7.2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/9ada3931beb37068fcb725b34b0398457009f343"}, {"url": "https://git.kernel.org/stable/c/5f470cc883416fea6d3bce18ef96bf91dd49ffc3"}, {"url": "https://git.kernel.org/stable/c/5801cff7d5d7b4e9d877dfb627b23eb63167f02c"}], "title": "rxrpc: Don't move a peeked OOB message onto the pending queue", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/rxrpc/recvmsg.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "9ada3931beb37068fcb725b34b0398457009f343", "status": "affected", "version": "5800b1cf3fd8ccab752a101865be1e76dac33142", "versionType": "git"}, {"lessThan": "5f470cc883416fea6d3bce18ef96bf91dd49ffc3", "status": "affected", "version": "5800b1cf3fd8ccab752a101865be1e76dac33142", "versionType": "git"}, {"lessThan": "5801cff7d5d7b4e9d877dfb627b23eb63167f02c", "status": "affected", "version": "5800b1cf3fd8ccab752a101865be1e76dac33142", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/rxrpc/recvmsg.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": "6.18.40", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.5", "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\nrxrpc: Don't move a peeked OOB message onto the pending queue\n\nrxrpc_recvmsg_oob() takes a received oob message off recvmsg_oobq and,\nif a response is needed, moves it onto the pending_oobq tree. However,\nonly the unlink from recvmsg_oobq is guarded by MSG_PEEK; the move onto\npending_oobq always runs.\n\nAs a result, reading a challenge with MSG_PEEK leaves the skb on\nrecvmsg_oobq while also adding it to pending_oobq. Since struct\nsk_buff's rbnode shares storage with its next and prev pointers,\nrb_insert_color() overwrites the list linkage, and the skb, which holds\na single reference, becomes reachable from both queues at once.\n\nWhen the socket is closed both queues are drained in turn. While\ndraining recvmsg_oobq, __skb_unlink() follows the next and prev\npointers that rbnode has overwritten and writes to a bad address. Also,\nas the skb holds a single reference but is freed from each queue, both\nthe skb and the connection reference it holds are released twice. This\nleads to memory corruption and to a use-after-free caused by the\nconnection refcount underflow.\n\nMSG_PEEK does not consume the message from the queue, so only unlink it\nfrom recvmsg_oobq and then move it onto pending_oobq or free it when\nthe message is actually consumed."}], "id": "CVE-2026-74434", "lastModified": "2026-08-17T06:19:39.030", "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": "2026-08-15T06:22:45.510", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/5801cff7d5d7b4e9d877dfb627b23eb63167f02c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/5f470cc883416fea6d3bce18ef96bf91dd49ffc3"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/9ada3931beb37068fcb725b34b0398457009f343"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: rxrpc: Don't move a peeked OOB message onto the pending queue", "id": "2516819", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2516819"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-1341", "details": ["A flaw was found in the Linux kernel's rxrpc subsystem. When an out-of-band (OOB) message is read using the MSG_PEEK flag in the rxrpc_recvmsg_oob() function, the message is incorrectly left on one queue while also being added to another. This can lead to the message being freed twice when the socket is closed, resulting in memory corruption and a use-after-free vulnerability. A local attacker could exploit this to cause system instability or potentially execute arbitrary code."], "name": "CVE-2026-74434", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "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": "2026-08-15T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-74434\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-74434\nhttps://lore.kernel.org/linux-cve-announce/2026081515-CVE-2026-74434-3ec5@gregkh/T"], "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[5800b1cf3fd8ccab752a101865be1e76dac33142,9ada3931beb37068fcb725b34b0398457009f343)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[5800b1cf3fd8ccab752a101865be1e76dac33142,5f470cc883416fea6d3bce18ef96bf91dd49ffc3)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[5800b1cf3fd8ccab752a101865be1e76dac33142,5801cff7d5d7b4e9d877dfb627b23eb63167f02c)"}}], "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": "generic", "value": "[6.18.40,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.1.5,7.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2-rc1,*]"}}], "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": "2026-08-15T17:30:11.723596+00:00", "updated": "2026-08-21T21:30:17.772287+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-1341", "CWE-416"]}