{ "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" } } ] } }