{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-21763","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2024-12-29T08:45:45.761Z","datePublished":"2025-02-27T02:18:15.078Z","dateUpdated":"2026-08-05T11:54:16.348Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T11:54:16.348Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nneighbour: use RCU protection in __neigh_notify()\n\n__neigh_notify() can be called without RTNL or RCU protection.\n\nUse RCU protection to avoid potential UAF."}],"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 - The decisive side of the race — `dev_net_set()` during netdevice namespace migration or `default_device_exit_batch()` on netns teardown, followed by freeing the `struct net` — is driven only by local syscalls (`unshare(CLONE_NEWNET|CLONE_NEWUSER)`, RTM_NEWLINK/RTM_SETLINK). A purely remote or adjacent peer can generate ARP/NDISC traffic to reach `__neigh_notify()` but cannot cause the namespace pointer to go stale.\nAC:L - The attacker controls both sides: they spin a loop creating/destroying network namespaces with veth devices while concurrently driving neighbour add/update/GC notifications on other CPUs, so the race is created rather than waited for. Per race-condition guidance, attacker-created races are Low even though the window between the `dev_net()` load and the `net->rtnl` dereference is narrow.\nPR:L - `unshare -Urn` grants namespace-relative CAP_NET_ADMIN (`ns_capable(net->user_ns, CAP_NET_ADMIN)`), letting an ordinary unprivileged user create netns, create and move veth pairs, and trigger the teardown path; no real root is needed. Neighbour-table activity that reaches `__neigh_notify()` is likewise available to any unprivileged process.\nUI:N - The attacker triggers both the namespace teardown and the neighbour notifications entirely from their own processes. No victim action, mount, or file open is involved.\nS:U - The use-after-free and its consequences are confined to kernel memory within the same security authority; no VM, IOMMU, or sandbox boundary is crossed. This is standard in-kernel corruption leading to local privilege escalation.\nC:H - The freed `struct net` is a reclaimable `net_cachep` slab object, and `net->rtnl` is subsequently consumed as a `struct sock *` by `netlink_set_err()`/`nlmsg_notify()`, which read `sk->sk_protocol` and `sock_net(sk)` and walk netlink tables from it. Heap-spraying the freed object turns this into an attacker-directed kernel read primitive.\nI:H - With the freed `struct net` reclaimed under attacker control, `netlink_set_err()` writes through the forged `sk` pointer (`sk->sk_err = err`, list/waitqueue manipulation), giving a controlled kernel write usable for control-flow hijacking. Per guidance, use-after-free is scored High for integrity.\nA:H - Even without successful reclaim, dereferencing the freed `struct net` and the dangling `net->rtnl` socket causes a kernel oops or panic in `nlmsg_notify()`/`netlink_set_err()`. The trigger loop can be repeated indefinitely by an unprivileged user."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/neighbour.c"],"versions":[{"version":"426b5303eb435d98b9bee37a807be386bc2b3320","lessThan":"e1aed6be381bcd7f46d4ca9d7ef0f5f3d6a1be32","status":"affected","versionType":"git"},{"version":"426b5303eb435d98b9bee37a807be386bc2b3320","lessThan":"8666e9aab801328c1408a19fbf4070609dc0695a","status":"affected","versionType":"git"},{"version":"426b5303eb435d98b9bee37a807be386bc2b3320","lessThan":"40d8f2f2a373b6c294ffac394d2bb814b572ead1","status":"affected","versionType":"git"},{"version":"426b5303eb435d98b9bee37a807be386bc2b3320","lessThan":"784eb2376270e086f7db136d154b8404edacf97b","status":"affected","versionType":"git"},{"version":"426b5303eb435d98b9bee37a807be386bc2b3320","lessThan":"1cbb2aa90cd3fba15ad7efb5cdda28f3d1082379","status":"affected","versionType":"git"},{"version":"426b5303eb435d98b9bee37a807be386bc2b3320","lessThan":"cdd5c2a12ddad8a77ce1838ff9f29aa587de82df","status":"affected","versionType":"git"},{"version":"426b5303eb435d98b9bee37a807be386bc2b3320","lessThan":"559307d25235e24b5424778c7332451b6c741159","status":"affected","versionType":"git"},{"version":"426b5303eb435d98b9bee37a807be386bc2b3320","lessThan":"becbd5850c03ed33b232083dd66c6e38c0c0e569","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/core/neighbour.c"],"versions":[{"version":"2.6.25","status":"affected"},{"version":"0","lessThan":"2.6.25","status":"unaffected","versionType":"semver"},{"version":"5.4.291","lessThanOrEqual":"5.4.*","status":"unaffected","versionType":"semver"},{"version":"5.10.235","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.179","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.129","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.79","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.16","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.13.4","lessThanOrEqual":"6.13.*","status":"unaffected","versionType":"semver"},{"version":"6.14","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":"2.6.25","versionEndExcluding":"5.4.291"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.25","versionEndExcluding":"5.10.235"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.25","versionEndExcluding":"5.15.179"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.25","versionEndExcluding":"6.1.129"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.25","versionEndExcluding":"6.6.79"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.25","versionEndExcluding":"6.12.16"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.25","versionEndExcluding":"6.13.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.25","versionEndExcluding":"6.14"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/e1aed6be381bcd7f46d4ca9d7ef0f5f3d6a1be32"},{"url":"https://git.kernel.org/stable/c/8666e9aab801328c1408a19fbf4070609dc0695a"},{"url":"https://git.kernel.org/stable/c/40d8f2f2a373b6c294ffac394d2bb814b572ead1"},{"url":"https://git.kernel.org/stable/c/784eb2376270e086f7db136d154b8404edacf97b"},{"url":"https://git.kernel.org/stable/c/1cbb2aa90cd3fba15ad7efb5cdda28f3d1082379"},{"url":"https://git.kernel.org/stable/c/cdd5c2a12ddad8a77ce1838ff9f29aa587de82df"},{"url":"https://git.kernel.org/stable/c/559307d25235e24b5424778c7332451b6c741159"},{"url":"https://git.kernel.org/stable/c/becbd5850c03ed33b232083dd66c6e38c0c0e569"}],"title":"neighbour: use RCU protection in __neigh_notify()","x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":7.8,"attackVector":"LOCAL","baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","integrityImpact":"HIGH","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"LOW","confidentialityImpact":"HIGH"}},{"other":{"type":"ssvc","content":{"id":"CVE-2025-21763","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2025-02-27T17:57:24.552153Z"}}}],"problemTypes":[{"descriptions":[{"lang":"en","type":"CWE","cweId":"CWE-416","description":"CWE-416 Use After Free"}]}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2025-02-27T18:02:26.961Z"}},{"title":"CVE Program Container","references":[{"url":"https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html"},{"url":"https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html"}],"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2025-11-03T19:37:14.329Z"}},{"x_adpType":"supplier","providerMetadata":{"orgId":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e","shortName":"siemens-SADP","dateUpdated":"2026-05-12T12:03:44.302Z"},"affected":[{"vendor":"Siemens","product":"SIMATIC S7-1500 TM MFP - GNU/Linux subsystem","versions":[{"status":"affected","version":"0","lessThan":"*","versionType":"custom"}],"defaultStatus":"unknown"}],"references":[{"url":"https://cert-portal.siemens.com/productcert/html/ssa-265688.html"}]}]}}