{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-38550","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-04-16T04:51:24.024Z","datePublished":"2025-08-16T11:34:18.619Z","dateUpdated":"2026-08-05T12:02:49.916Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:02:49.916Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: mcast: Delay put pmc->idev in mld_del_delrec()\n\npmc->idev is still used in ip6_mc_clear_src(), so as mld_clear_delrec()\ndoes, the reference should be put after ip6_mc_clear_src() return."}],"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 vulnerable `mld_del_delrec()` path is entered from IPv6 multicast socket options (`IPV6_ADD_MEMBERSHIP`/`MCAST_JOIN_GROUP`) via `ipv6_sock_mc_join()` → `__ipv6_dev_mc_inc()`, which requires a local socket and local syscall access. The secondary `ipv6_mc_up()` call site is likewise local (RTNL/admin), so no remote packet processing reaches this code directly.\nAC:L - The attacker deterministically creates the required state himself — join a group, drop it (creating the `mc_tomb` entry through `mld_add_delrec()` in the default MLDv2 mode), then rejoin — with no race to win and no memory-layout precondition outside his control. All steps are ordinary `setsockopt()` calls that succeed on the first try.\nPR:L - Only an unprivileged local account is needed; `ipv6_sock_mc_join()`/`ipv6_sock_mc_drop()` perform no capability check, and joining a global-scope IPv6 multicast group is permitted to any user holding an `AF_INET6` socket. No `CAP_NET_ADMIN` or root is required, and the path is equally available inside an unprivileged user namespace with a veth/dummy device.\nUI:N - The entire sequence is driven by the attacker's own socket calls in a single process. No victim action, no filesystem mount, and no administrator involvement is needed.\nS:U - The premature reference drop and its consequences are confined to the kernel's own `inet6_dev` allocation and the network namespace that owns it. No hypervisor, IOMMU, or sandbox boundary is crossed, so the vulnerable component and impacted component share one security authority.\nC:H - Dropping the `inet6_dev` reference before `ip6_mc_clear_src()` finishes using `pmc->idev` is a use-after-free pattern on a refcounted network structure; once the object can be reclaimed, an attacker who sprays the freed `inet6_dev` slab gains a read primitive over attacker-shaped heap contents and adjacent kernel data. Per the UAF guidance this warrants High rather than a bounded pointer leak.\nI:H - A use-after-free on `inet6_dev` gives the attacker control over the contents subsequently dereferenced through `pmc->idev`, including the `mc_lock`/list pointers reached from `mc_dereference()`, which is the standard basis for heap-spray-driven arbitrary write and control-flow hijack. Type-confused reuse of the freed slab makes kernel memory modification achievable rather than merely theoretical.\nA:H - If the released reference is the last one, the following `ip6_mc_clear_src()` operates on freed memory, producing an oops or panic and taking the whole kernel down. The trigger is a repeatable unprivileged `setsockopt()` loop, so the crash can be induced at will."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv6/mcast.c"],"versions":[{"version":"b564ec4491d24b40900c64ab9e29a208f17f3108","lessThan":"1b5b413094af8d88a31b5df3fd262f6baca53841","status":"affected","versionType":"git"},{"version":"63ed8de4be81b699ca727e9f8e3344bd487806d7","lessThan":"6e4eec86fe5f6b3fdbc702d1d36ac2a6e7ec0806","status":"affected","versionType":"git"},{"version":"63ed8de4be81b699ca727e9f8e3344bd487806d7","lessThan":"728db00a14cacb37f36e9382ab5fad55caf890cc","status":"affected","versionType":"git"},{"version":"63ed8de4be81b699ca727e9f8e3344bd487806d7","lessThan":"dcbc346f50a009d8b7f4e330f9f2e22d6442fa26","status":"affected","versionType":"git"},{"version":"63ed8de4be81b699ca727e9f8e3344bd487806d7","lessThan":"7929d27c747eafe8fca3eecd74a334503ee4c839","status":"affected","versionType":"git"},{"version":"63ed8de4be81b699ca727e9f8e3344bd487806d7","lessThan":"5f18e0130194550dff734e155029ae734378b5ea","status":"affected","versionType":"git"},{"version":"63ed8de4be81b699ca727e9f8e3344bd487806d7","lessThan":"ae3264a25a4635531264728859dbe9c659fad554","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/ipv6/mcast.c"],"versions":[{"version":"5.13","status":"affected"},{"version":"0","lessThan":"5.13","status":"unaffected","versionType":"semver"},{"version":"5.15.190","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.147","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.100","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.40","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.15.8","lessThanOrEqual":"6.15.*","status":"unaffected","versionType":"semver"},{"version":"6.16","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":"5.13","versionEndExcluding":"5.15.190"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.1.147"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.6.100"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.12.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.15.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.16"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/1b5b413094af8d88a31b5df3fd262f6baca53841"},{"url":"https://git.kernel.org/stable/c/6e4eec86fe5f6b3fdbc702d1d36ac2a6e7ec0806"},{"url":"https://git.kernel.org/stable/c/728db00a14cacb37f36e9382ab5fad55caf890cc"},{"url":"https://git.kernel.org/stable/c/dcbc346f50a009d8b7f4e330f9f2e22d6442fa26"},{"url":"https://git.kernel.org/stable/c/7929d27c747eafe8fca3eecd74a334503ee4c839"},{"url":"https://git.kernel.org/stable/c/5f18e0130194550dff734e155029ae734378b5ea"},{"url":"https://git.kernel.org/stable/c/ae3264a25a4635531264728859dbe9c659fad554"}],"title":"ipv6: mcast: Delay put pmc->idev in mld_del_delrec()","x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CVE Program Container","references":[{"url":"https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"}],"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2025-11-03T17:39:43.796Z"}}]}}