{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2024-26631", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-02-19T14:20:24.136Z", "datePublished": "2024-03-18T10:07:48.346Z", "dateUpdated": "2026-08-05T11:26:24.727Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:26:24.727Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: mcast: fix data-race in ipv6_mc_down / mld_ifc_work\n\nidev->mc_ifc_count can be written over without proper locking.\n\nOriginally found by syzbot [1], fix this issue by encapsulating calls\nto mld_ifc_stop_work() (and mld_gq_stop_work() for good measure) with\nmutex_lock() and mutex_unlock() accordingly as these functions\nshould only be called with mc_lock per their declarations.\n\n[1]\nBUG: KCSAN: data-race in ipv6_mc_down / mld_ifc_work\n\nwrite to 0xffff88813a80c832 of 1 bytes by task 3771 on cpu 0:\n mld_ifc_stop_work net/ipv6/mcast.c:1080 [inline]\n ipv6_mc_down+0x10a/0x280 net/ipv6/mcast.c:2725\n addrconf_ifdown+0xe32/0xf10 net/ipv6/addrconf.c:3949\n addrconf_notify+0x310/0x980\n notifier_call_chain kernel/notifier.c:93 [inline]\n raw_notifier_call_chain+0x6b/0x1c0 kernel/notifier.c:461\n __dev_notify_flags+0x205/0x3d0\n dev_change_flags+0xab/0xd0 net/core/dev.c:8685\n do_setlink+0x9f6/0x2430 net/core/rtnetlink.c:2916\n rtnl_group_changelink net/core/rtnetlink.c:3458 [inline]\n __rtnl_newlink net/core/rtnetlink.c:3717 [inline]\n rtnl_newlink+0xbb3/0x1670 net/core/rtnetlink.c:3754\n rtnetlink_rcv_msg+0x807/0x8c0 net/core/rtnetlink.c:6558\n netlink_rcv_skb+0x126/0x220 net/netlink/af_netlink.c:2545\n rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:6576\n netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline]\n netlink_unicast+0x589/0x650 net/netlink/af_netlink.c:1368\n netlink_sendmsg+0x66e/0x770 net/netlink/af_netlink.c:1910\n ...\n\nwrite to 0xffff88813a80c832 of 1 bytes by task 22 on cpu 1:\n mld_ifc_work+0x54c/0x7b0 net/ipv6/mcast.c:2653\n process_one_work kernel/workqueue.c:2627 [inline]\n process_scheduled_works+0x5b8/0xa30 kernel/workqueue.c:2700\n worker_thread+0x525/0x730 kernel/workqueue.c:2781\n ..." } ], "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 `ipv6_mc_down()` side of the race is reached through local rtnetlink (`RTM_SETLINK`/`RTM_DELLINK` → `addrconf_notify`) and the opposing side through `setsockopt(IPV6_ADD_MEMBERSHIP)`, both local syscall interfaces. Although `mld_query_work` can additionally be fed by MLD query packets from a link-local peer, an adjacent attacker cannot initiate the interface-down half, so the self-contained attack is local.\nAC:L - The attacker drives both sides of the race deterministically and repeatedly: multicast join/leave and injected MLD queries queue `mc_ifc_work`/`mc_gq_work` while a concurrent thread loops `ip link set dev X down`, and `ipv6_mc_down()` uses non-sync `cancel_delayed_work()` for the query worker, guaranteeing an overlapping window on every iteration.\nPR:L - The rtnetlink gate is `netlink_net_capable(skb, CAP_NET_ADMIN)` → `netlink_ns_capable(..., sock_net(skb->sk)->user_ns, ...)`, which an unprivileged user obtains in a fresh netns via `unshare -Urn`; the multicast-join side requires no privilege at all.\nUI:N - The attacker performs every step — creating the device, joining groups, injecting MLD queries, and toggling the link down — with no victim action required.\nS:U - The corruption is confined to kernel IPv6 multicast state and the `inet6_dev` object within the same kernel security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The unserialized `cancel_delayed_work()`/`in6_dev_hold()` window permits an `idev->refcnt` underflow through `__in6_dev_put()`'s unchecked `refcount_dec()`, leading to premature `kfree(idev)` while MLD workers still dereference it; a use-after-free on a kmalloc'd `inet6_dev` gives the attacker reads of resprayed heap contents.\nI:H - The same use-after-free is a write primitive: `struct inet6_dev` embeds five `delayed_work` structures whose `work->func` pointers the workqueue dispatches, plus `rs_timer` and `nd_parms`, so a resprayed object yields control-flow hijack; the race also corrupts adjacent packed fields (`mc_qrv`, `mc_gq_running`) that steer subsequent MLD state.\nA:H - The opposite interleaving orphans an `inet6_dev` reference so `in6_dev_finish_destroy()`/`netdev_put()` never run, wedging `unregister_netdevice: waiting for … to become free` permanently and blocking netns teardown under rtnl; the underflow direction produces `refcount_t` warnings and an oops." } ] } ], "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": "07a7a183f22cf1e3ce5ed336fe62a6248a2f6738", "lessThan": "75ddcd741d2a30696f5893bc71a9d28f4ef22311", "status": "affected", "versionType": "git" }, { "version": "2d9a93b4902be6a5504b5941dd15e9cd776aadca", "lessThan": "62b3387beef11738eb6ce667601a28fa089fa02c", "status": "affected", "versionType": "git" }, { "version": "2d9a93b4902be6a5504b5941dd15e9cd776aadca", "lessThan": "380540bb06bb1d1b12bdc947d1b8f56cda6b5663", "status": "affected", "versionType": "git" }, { "version": "2d9a93b4902be6a5504b5941dd15e9cd776aadca", "lessThan": "3cc283fd16fba72e2cefe3a6f48d7a36b0438900", "status": "affected", "versionType": "git" }, { "version": "2d9a93b4902be6a5504b5941dd15e9cd776aadca", "lessThan": "3bb5849675ae1d592929798a2b37ea450879c855", "status": "affected", "versionType": "git" }, { "version": "2d9a93b4902be6a5504b5941dd15e9cd776aadca", "lessThan": "2e7ef287f07c74985f1bf2858bedc62bd9ebf155", "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": "5.15.148", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.75", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.14", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.7.2", "lessThanOrEqual": "6.7.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.8", "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": "5.15.148" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13", "versionEndExcluding": "6.1.75" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13", "versionEndExcluding": "6.6.14" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13", "versionEndExcluding": "6.7.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13", "versionEndExcluding": "6.8" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/75ddcd741d2a30696f5893bc71a9d28f4ef22311" }, { "url": "https://git.kernel.org/stable/c/62b3387beef11738eb6ce667601a28fa089fa02c" }, { "url": "https://git.kernel.org/stable/c/380540bb06bb1d1b12bdc947d1b8f56cda6b5663" }, { "url": "https://git.kernel.org/stable/c/3cc283fd16fba72e2cefe3a6f48d7a36b0438900" }, { "url": "https://git.kernel.org/stable/c/3bb5849675ae1d592929798a2b37ea450879c855" }, { "url": "https://git.kernel.org/stable/c/2e7ef287f07c74985f1bf2858bedc62bd9ebf155" } ], "title": "ipv6: mcast: fix data-race in ipv6_mc_down / mld_ifc_work", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-02T00:07:19.693Z" }, "title": "CVE Program Container", "references": [ { "url": "https://git.kernel.org/stable/c/62b3387beef11738eb6ce667601a28fa089fa02c", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/380540bb06bb1d1b12bdc947d1b8f56cda6b5663", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/3cc283fd16fba72e2cefe3a6f48d7a36b0438900", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/3bb5849675ae1d592929798a2b37ea450879c855", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/2e7ef287f07c74985f1bf2858bedc62bd9ebf155", "tags": [ "x_transferred" ] } ] }, { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2024-08-27T14:55:41.665799Z", "id": "CVE-2024-26631", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-08-27T14:55:52.147Z" } } ] } }