{"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"}}}}