{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-21758", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-12-29T08:45:45.761Z", "datePublished": "2025-02-27T02:18:12.496Z", "dateUpdated": "2026-08-05T11:54:10.964Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:54:10.964Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: mcast: add RCU protection to mld_newpack()\n\nmld_newpack() can be called without RTNL or RCU being held.\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 - The half of the race that mutates `dev->nd_net` (`dev_change_net_namespace()` / netns teardown) requires local action — network namespace creation and device moves — so the attack must be mounted locally. The MLD report path itself is also reachable by an adjacent attacker's MLD Query, but a remote peer alone cannot create the racing `dev_net()` mutation.\nAC:L - The attacker controls both sides of the race: they schedule the MLD report work at will (unprivileged multicast join, or by driving `igmp6_event_query`) and simultaneously perform the netns creation/destruction or device namespace move that flips `dev->nd_net`, looping until the window is hit. `cancel_delayed_work()` in `mld_ifc_stop_work`/`mld_gq_stop_work` is non-synchronous and `__mld_query_work` can re-arm `mc_gq_work` afterwards, so no barrier closes the window.\nPR:L - Joining an IPv6 multicast group via `setsockopt(IPV6_ADD_MEMBERSHIP)` needs no privilege at all, and the netns/netdev manipulation side is reachable by an ordinary user through unprivileged user namespaces (`unshare -Urn` grants CAP_NET_ADMIN inside the new netns). No real root in the init namespace is required.\nUI:N - The attacker drives both the multicast join and the namespace churn from their own processes; no victim action or cooperation is needed.\nS:U - The corruption is confined to kernel memory within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The stale `struct net *` yields a use-after-free read of freed slab memory and a dangling `struct sock *`, and `ip6_mc_hdr()` copies `inet6_sk(sk)->hop_limit` out of that freed object directly into a transmitted IPv6 header — leaking reclaimed kernel heap contents onto the network, with the UAF generally usable as a broader read primitive.\nI:H - `sock_alloc_send_skb()` performs refcount and ownership writes into the freed socket, and the skb's `sock_wfree` destructor later makes an indirect call through `sk->sk_write_space` in memory an unprivileged attacker can reclaim by spraying raw IPv6 sockets — a control-flow hijack primitive, not merely a stray write.\nA:H - Dereferencing a freed `struct net`/`struct sock` reliably oopses or panics the kernel (KASAN-detectable UAF), and the race can be retried in a loop until it lands." } ] } ], "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": "29fa42197f26a97cde29fa8c40beddf44ea5c8f3", "status": "affected", "versionType": "git" }, { "version": "b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551", "lessThan": "e8af3632a7f2da83e27b083f787bced1faba00b1", "status": "affected", "versionType": "git" }, { "version": "b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551", "lessThan": "1b91c597b0214b1b462eb627ec02658c944623f2", "status": "affected", "versionType": "git" }, { "version": "b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551", "lessThan": "25195f9d5ffcc8079ad743a50c0409dbdc48d98a", "status": "affected", "versionType": "git" }, { "version": "b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551", "lessThan": "d60d493b0e65647e0335e6a7c4547abcea7df8e9", "status": "affected", "versionType": "git" }, { "version": "b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551", "lessThan": "a527750d877fd334de87eef81f1cb5f0f0ca3373", "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": "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": "2.6.26", "versionEndExcluding": "5.15.179" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.26", "versionEndExcluding": "6.1.129" }, { "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/29fa42197f26a97cde29fa8c40beddf44ea5c8f3" }, { "url": "https://git.kernel.org/stable/c/e8af3632a7f2da83e27b083f787bced1faba00b1" }, { "url": "https://git.kernel.org/stable/c/1b91c597b0214b1b462eb627ec02658c944623f2" }, { "url": "https://git.kernel.org/stable/c/25195f9d5ffcc8079ad743a50c0409dbdc48d98a" }, { "url": "https://git.kernel.org/stable/c/d60d493b0e65647e0335e6a7c4547abcea7df8e9" }, { "url": "https://git.kernel.org/stable/c/a527750d877fd334de87eef81f1cb5f0f0ca3373" } ], "title": "ipv6: mcast: add RCU protection to mld_newpack()", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "title": "CVE Program Container", "references": [ { "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T19:37:03.144Z" } }, { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-07-14T12:39:59.324Z" }, "affected": [ { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.5", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.6", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": 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