{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-74689", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.926Z", "datePublished": "2026-08-22T15:32:54.034Z", "dateUpdated": "2026-10-16T19:16:09.361Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-25T05:41:33.932Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/atm: fix slab-out-of-bounds read in vcc_setsockopt()\n\nvcc_setsockopt() contained an ineffective optlen check:\n if (__SO_LEVEL_MATCH(optname, level) && optlen != __SO_SIZE(optname))\n return -EINVAL;\n\nIf __SO_LEVEL_MATCH(optname, level) evaluated to false (e.g. if the caller\npassed a mismatched level), the length check optlen != __SO_SIZE(optname)\nwas short-circuited and bypassed. Execution then fell through to switch(optname),\ncalling copy_from_sockptr() assuming optval contained sufficient space.\n\nFurthermore, even if level matched, a cgroup BPF setsockopt filter could shrink\noptlen after entry. Because copy_from_sockptr() on kernel pointers uses memcpy(),\nthis leads to a KASAN slab-out-of-bounds read when optlen is smaller than the\nexpected structure size.\n\nFix this by using copy_safe_from_sockptr(), which unconditionally validates\nthat optlen is at least the expected size before copying. Also change the local\n'value' variable type from 'unsigned long' to 'int' so that SO_SETCLP matches\nits sizeof(int) ABI encoding on 64-bit systems." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H", "baseScore": 7.1, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The bug is reached only via the local setsockopt(2) syscall on an AF_ATMPVC/AF_ATMSVC socket (do_sock_setsockopt -> pvc_setsockopt/svc_setsockopt -> vcc_setsockopt); no remote ATM packet or network-facing handler invokes this path.\nAC:L - The attacker fully controls level, optname, and optlen; passing a mismatched level bypasses the short-circuited length check, and cgroup BPF setsockopt can shrink optlen after entry, deterministically triggering a full-size memcpy past a small kmalloc buffer with no race.\nPR:L - No capability check guards SO_ATMQOS or SO_SETCLP on unconnected ATM sockets; any unprivileged local user in init_net (required because ATM socket creation rejects non-init network namespaces) can open AF_ATMPVC sockets and issue the crafted setsockopt without CAP_NET_ADMIN.\nUI:N - The attacker triggers the out-of-bounds read entirely from their own process with a single crafted setsockopt call; no victim interaction or cooperation is required.\nS:U - Impact is kernel heap memory disclosure and potential crash within the host kernel security boundary; no VM escape, IOMMU bypass, or cross-sandbox boundary crossing occurs.\nC:H - copy_from_sockptr() performs a slab-out-of-bounds read of up to 92 bytes (struct atm_qos) or 8 bytes (SO_SETCLP) past a kmalloc buffer into kernel stack memory; adjacent slab contents can populate vcc->qos and be retrieved via subsequent SO_ATMQOS getsockopt.\nI:N - The defect is a pure out-of-bounds read with no arbitrary kernel write, heap corruption, or control-flow hijack primitive; although leaked bytes may influence vcc->qos if validation passes, no attacker-controlled data modification occurs.\nA:H - The KASAN-reported slab-out-of-bounds read triggers kernel oops on hardened kernels, and reading past a small kmalloc object into adjacent slab memory on production kernels risks faulting on unmapped redzone pages or corrupting adjacent objects leading to panic." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/atm/common.c" ], "versions": [ { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "b3bcd5d65ac03c15787b2a5b36c718e26a689336", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "35f258fee9ed358c6d0f57f91c30bf029c3724af", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "6eb6af88710977eb529b558a07294874d8c40c4d", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "9f77c1ab382188f5b51982fab6d913443b6dc59f", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "2c5988c7349c0b64a7e0441bfc6e1dca54f7116a", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "d0c80dbb970439bd2eeb0e5effff8c16a5f4e1e3", "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/atm/common.c" ], "versions": [ { "version": "2.6.12", "status": "affected" }, { "version": "0", "lessThan": "2.6.12", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.183", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.152", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.104", "lessThanOrEqual": "6.12.*", "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": "2.6.12", "versionEndExcluding": "6.1.183" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.6.152" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.12.104" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.18.45" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "7.1.9" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/b3bcd5d65ac03c15787b2a5b36c718e26a689336" }, { "url": "https://git.kernel.org/stable/c/35f258fee9ed358c6d0f57f91c30bf029c3724af" }, { "url": "https://git.kernel.org/stable/c/6eb6af88710977eb529b558a07294874d8c40c4d" }, { "url": "https://git.kernel.org/stable/c/9f77c1ab382188f5b51982fab6d913443b6dc59f" }, { "url": "https://git.kernel.org/stable/c/2c5988c7349c0b64a7e0441bfc6e1dca54f7116a" }, { "url": "https://git.kernel.org/stable/c/d0c80dbb970439bd2eeb0e5effff8c16a5f4e1e3" } ], "title": "net/atm: fix slab-out-of-bounds read in vcc_setsockopt()", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2026-74689", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2026-10-16T19:14:36.506932Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:16:09.361Z" } } ] } }