{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-31675", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-03-09T15:48:24.130Z", "datePublished": "2026-04-25T08:46:51.184Z", "dateUpdated": "2026-08-05T12:24:22.485Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:24:22.485Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_netem: fix out-of-bounds access in packet corruption\n\nIn netem_enqueue(), the packet corruption logic uses\nget_random_u32_below(skb_headlen(skb)) to select an index for\nmodifying skb->data. When an AF_PACKET TX_RING sends fully non-linear\npackets over an IPIP tunnel, skb_headlen(skb) evaluates to 0.\n\nPassing 0 to get_random_u32_below() takes the variable-ceil slow path\nwhich returns an unconstrained 32-bit random integer. Using this\nunconstrained value as an offset into skb->data results in an\nout-of-bounds memory access.\n\nFix this by verifying skb_headlen(skb) is non-zero before attempting\nto corrupt the linear data area. Fully non-linear packets will silently\nbypass the corruption logic." } ], "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 - Triggering requires local kernel interfaces: configuring a `netem` qdisc via rtnetlink and sending crafted AF_PACKET TX_RING traffic over an IPIP tunnel. This is not directly reachable by unauthenticated remote packets.\nAC:L - The attacker controls the qdisc corruption setting and the fully non-linear skb construction path, with no race or victim state required. The corrupt probability can be configured to make the vulnerable access occur reliably.\nPR:L - The path requires `CAP_NET_ADMIN` for traffic control and `CAP_NET_RAW` for AF_PACKET, but both are obtainable inside attacker-created user/network namespaces on systems permitting unprivileged user namespaces. Therefore this is low privilege rather than real init-namespace root.\nUI:N - No victim action is needed once the local attacker can issue the relevant netlink and socket syscalls. The attacker triggers the enqueue path directly.\nS:U - The corruption occurs within the kernel networking/qdisc subsystem and impacts the same kernel security authority. It is a standard local kernel compromise scenario, not a VM or hardware boundary escape.\nC:H - The bug is an out-of-bounds kernel memory read-modify-write through an unconstrained offset from `skb->data`. As kernel memory corruption, successful exploitation can plausibly yield arbitrary kernel memory disclosure.\nI:H - The vulnerable operation flips a bit at an out-of-bounds kernel address, giving a kernel memory corruption primitive. Under the required overestimation rule, this supports potential control-flow hijack or privilege escalation.\nA:H - The unconstrained out-of-bounds kernel access can fault or corrupt critical kernel memory. A local attacker can repeatedly trigger it, making kernel oops/panic or system instability high impact." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sched/sch_netem.c" ], "versions": [ { "version": "c865e5d99e25a171e8262fc0f7ba608568633c64", "lessThan": "a14b56863348686dd0387eea8ce66b85cf455908", "status": "affected", "versionType": "git" }, { "version": "c865e5d99e25a171e8262fc0f7ba608568633c64", "lessThan": "13a66ca1e235d4bcd53d12d4c68490cad7f8e46f", "status": "affected", "versionType": "git" }, { "version": "c865e5d99e25a171e8262fc0f7ba608568633c64", "lessThan": "3a2999704ac36cfb4041fed3652d26a3373e8d12", "status": "affected", "versionType": "git" }, { "version": "c865e5d99e25a171e8262fc0f7ba608568633c64", "lessThan": "4fd258e281fa8bc15e9ce2c7691941537e9258ad", "status": "affected", "versionType": "git" }, { "version": "c865e5d99e25a171e8262fc0f7ba608568633c64", "lessThan": "d64cb81dcbd54927515a7f65e5e24affdc73c14b", "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/sched/sch_netem.c" ], "versions": [ { "version": "2.6.16", "status": "affected" }, { "version": "0", "lessThan": "2.6.16", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.134", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.81", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.22", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.12", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0", "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": "2.6.16", "versionEndExcluding": "6.6.134" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.16", "versionEndExcluding": "6.12.81" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.16", "versionEndExcluding": "6.18.22" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.16", "versionEndExcluding": "6.19.12" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.16", "versionEndExcluding": "7.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/a14b56863348686dd0387eea8ce66b85cf455908" }, { "url": "https://git.kernel.org/stable/c/13a66ca1e235d4bcd53d12d4c68490cad7f8e46f" }, { "url": "https://git.kernel.org/stable/c/3a2999704ac36cfb4041fed3652d26a3373e8d12" }, { "url": "https://git.kernel.org/stable/c/4fd258e281fa8bc15e9ce2c7691941537e9258ad" }, { "url": "https://git.kernel.org/stable/c/d64cb81dcbd54927515a7f65e5e24affdc73c14b" } ], "title": "net/sched: sch_netem: fix out-of-bounds access in packet corruption", "x_generator": { "engine": "bippy-1.2.0" } } } }