{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-21759", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-12-29T08:45:45.761Z", "datePublished": "2025-02-27T02:18:12.994Z", "dateUpdated": "2026-08-05T11:54:12.048Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:54:12.048Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: mcast: extend RCU protection in igmp6_send()\n\nigmp6_send() can be called without RTNL or RCU being held.\n\nExtend RCU protection so that we can safely fetch the net pointer\nand avoid a potential UAF.\n\nNote that we no longer can use sock_alloc_send_skb() because\nipv6.igmp_sk uses GFP_KERNEL allocations which can sleep.\n\nInstead use alloc_skb() and charge the net->ipv6.igmp_sk\nsocket under RCU protection." } ], "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 - Although igmp6_send() can be scheduled by adjacent MLD Query packets, the freeing side of the race requires network-namespace dismantle or a netdev netns move, which is driven by local syscalls (unshare/setns, RTM_NEWLINK with IFLA_NET_NS_FD, process exit). A local unprivileged user controls both sides of the race entirely, making local access the reliable exploitation vector.\nAC:L - The attacker drives both halves: they schedule igmp6_send() at will (multicast join/leave, link up/down, or timed MLD reports) and trigger the free by destroying their own netns or moving the device out of it, and can retry the race indefinitely while heap-grooming the freed struct net/struct sock.\nPR:L - Only an unprivileged local account is needed — the CAP_NET_ADMIN checks on the netns-move path are ns_capable() against the target netns user_ns, which is satisfied inside a user namespace created with unshare -Urn, and IPv6 multicast joins require no privilege at all.\nUI:N - The entire sequence — namespace setup, multicast group joins, and namespace teardown — is performed by the attacker's own processes with no action from any other user.\nS:U - The corrupted objects (struct net, struct sock) and the resulting code execution are all within the kernel's own security authority; no hypervisor, IOMMU, or other security boundary is crossed.\nC:H - The use-after-free reads sk->sk_sndbuf, sk->sk_allocation, sk->sk_socket, net->mib pointers and net->nf.hooks_ipv6[] from freed-and-reallocated memory, giving an attacker who sprays the freed slab a controllable pointer-dereference primitive that can be turned into arbitrary kernel memory disclosure.\nI:H - skb_set_owner_w() performs refcount_add() into the freed socket and NF_HOOK() calls a function pointer fetched from the freed struct net's netfilter hook array, yielding both a write primitive and control-flow hijack suitable for full privilege escalation.\nA:H - Dereferencing a freed struct net and its igmp_sk reliably produces a kernel oops/panic (slab-use-after-free, invalid pointer dereference in the netfilter or socket accounting path), and the race can be repeated to crash the machine." } ] } ], "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": "b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551", "lessThan": "81b25a07ebf53f9ef4ca8f3d96a8ddb94561dd5a", "status": "affected", "versionType": "git" }, { "version": "b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551", "lessThan": "0bf8e2f3768629d437a32cb824149e6e98254381", "status": "affected", "versionType": "git" }, { "version": "b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551", "lessThan": "8e92d6a413feaf968a33f0b439ecf27404407458", "status": "affected", "versionType": "git" }, { "version": "b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551", "lessThan": "087c1faa594fa07a66933d750c0b2610aa1a2946", "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": "2.6.26", "status": "affected" }, { "version": "0", "lessThan": "2.6.26", "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": "2.6.26", "versionEndExcluding": "6.6.79" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.26", "versionEndExcluding": "6.12.16" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.26", "versionEndExcluding": "6.13.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.26", "versionEndExcluding": "6.14" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/81b25a07ebf53f9ef4ca8f3d96a8ddb94561dd5a" }, { "url": "https://git.kernel.org/stable/c/0bf8e2f3768629d437a32cb824149e6e98254381" }, { "url": "https://git.kernel.org/stable/c/8e92d6a413feaf968a33f0b439ecf27404407458" }, { "url": "https://git.kernel.org/stable/c/087c1faa594fa07a66933d750c0b2610aa1a2946" } ], "title": "ipv6: mcast: extend RCU protection in igmp6_send()", "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-2025-21759", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2025-02-27T17:57:46.460072Z" } } } ], "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": "2025-02-27T18:02:27.454Z" } } ] } }