{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-74436", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.896Z", "datePublished": "2026-08-15T05:59:34.687Z", "dateUpdated": "2026-08-23T12:47:16.782Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-23T12:47:16.782Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: serialize kernel accept preallocation with socket teardown\n\nrxrpc_kernel_charge_accept() reads rx->backlog without any\nsocket/backlog synchronization and passes that raw pointer into\nrxrpc_service_prealloc_one(). A concurrent rxrpc_discard_prealloc()\nsets rx->backlog = NULL and frees the backlog rings, so a kernel\npreallocation worker can keep using a freed struct rxrpc_backlog\nwhile updating *_backlog_head/tail and array slots.\n\nSerialize the state check and backlog lookup with the socket lock,\nand reject kernel preallocation once teardown has disabled\nlistening or discarded the service backlog." } ], "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 - RxRPC is a UDP network protocol; remote peers can send packets to AFS callback-manager listeners (port 7001) that instantiate incoming calls and queue kernel preallocation work reaching rxrpc_kernel_charge_accept().\nAC:L - The attacker controls the preallocation side by flooding concurrent rxrpc/AFS callback traffic while a peer thread tears down the same socket via listen(0), shutdown, or close during AFS netns exit, creating a winnable race.\nPR:N - No local account, capability, or authentication is required to reach the vulnerable preallocation path; any remote host that can deliver rxrpc/UDP packets to a listening AFS callback manager can drive the charge_accept worker.\nUI:N - Exploitation requires no victim interaction beyond normal background AFS service operation; the attacker triggers the bug purely through network traffic timed against automatic or administrative socket teardown.\nS:U - The use-after-free corrupts kernel heap metadata and rxrpc backlog structures within kernel memory, enabling local privilege escalation but not crossing a VM, container, or IOMMU security boundary by itself.\nC:H - Concurrent use of a freed struct rxrpc_backlog allows reads and corruption of recycled slab memory, providing a standard kmalloc UAF primitive that can leak kernel pointers and sensitive data.\nI:H - The race writes peer, connection, and call pointers plus head/tail indices into freed backlog ring slots, enabling heap grooming and arbitrary kernel memory corruption exploitable for code execution.\nA:H - Use-after-free on the backlog structure during concurrent head/tail and pointer-array updates can cause kernel oops, panic, or hang, and repeated triggering enables sustained denial of service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/rxrpc/call_accept.c" ], "versions": [ { "version": "00e907127e6f86d0f9b122d9b4347a8aa09a8b61", "lessThan": "d6207326b4ca0ae1041281b6af9df53f8080669a", "status": "affected", "versionType": "git" }, { "version": "00e907127e6f86d0f9b122d9b4347a8aa09a8b61", "lessThan": "11b429b84c87cb5a0152f14e7d6cb649ed363901", "status": "affected", "versionType": "git" }, { "version": "00e907127e6f86d0f9b122d9b4347a8aa09a8b61", "lessThan": "c20d983968f239574290cf804a58cde18ad1c559", "status": "affected", "versionType": "git" }, { "version": "00e907127e6f86d0f9b122d9b4347a8aa09a8b61", "lessThan": "0337cdba0c477f176c0459bed012109453184573", "status": "affected", "versionType": "git" }, { "version": "00e907127e6f86d0f9b122d9b4347a8aa09a8b61", "lessThan": "dfa0b2bbc5e50119f89c6b5407faa5ed86dfa7c5", "status": "affected", "versionType": "git" }, { "version": "00e907127e6f86d0f9b122d9b4347a8aa09a8b61", "lessThan": "35a967ff8b24db09ee429c39c5b5e6571639997d", "status": "affected", "versionType": "git" }, { "version": "00e907127e6f86d0f9b122d9b4347a8aa09a8b61", "lessThan": "1741378a7a83dfd8e53a9196730df709b903cd33", "status": "affected", "versionType": "git" }, { "version": "00e907127e6f86d0f9b122d9b4347a8aa09a8b61", "lessThan": "dc175389b18c29a5303ee83169ec653adfae3e17", "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/call_accept.c" ], "versions": [ { "version": "4.9", "status": "affected" }, { "version": "0", "lessThan": "4.9", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.266", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.217", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.184", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.148", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.101", "lessThanOrEqual": "6.12.*", "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": "4.9", "versionEndExcluding": "5.10.266" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "5.15.217" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.1.184" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.6.148" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.12.101" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/d6207326b4ca0ae1041281b6af9df53f8080669a" }, { "url": "https://git.kernel.org/stable/c/11b429b84c87cb5a0152f14e7d6cb649ed363901" }, { "url": "https://git.kernel.org/stable/c/c20d983968f239574290cf804a58cde18ad1c559" }, { "url": "https://git.kernel.org/stable/c/0337cdba0c477f176c0459bed012109453184573" }, { "url": "https://git.kernel.org/stable/c/dfa0b2bbc5e50119f89c6b5407faa5ed86dfa7c5" }, { "url": "https://git.kernel.org/stable/c/35a967ff8b24db09ee429c39c5b5e6571639997d" }, { "url": "https://git.kernel.org/stable/c/1741378a7a83dfd8e53a9196730df709b903cd33" }, { "url": "https://git.kernel.org/stable/c/dc175389b18c29a5303ee83169ec653adfae3e17" } ], "title": "rxrpc: serialize kernel accept preallocation with socket teardown", "x_generator": { "engine": "bippy-1.2.0" } } } }