{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2024-56759","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2024-12-29T11:26:39.761Z","datePublished":"2025-01-06T16:20:39.668Z","dateUpdated":"2026-08-05T11:46:23.511Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T11:46:23.511Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix use-after-free when COWing tree bock and tracing is enabled\n\nWhen a COWing a tree block, at btrfs_cow_block(), and we have the\ntracepoint trace_btrfs_cow_block() enabled and preemption is also enabled\n(CONFIG_PREEMPT=y), we can trigger a use-after-free in the COWed extent\nbuffer while inside the tracepoint code. This is because in some paths\nthat call btrfs_cow_block(), such as btrfs_search_slot(), we are holding\nthe last reference on the extent buffer @buf so btrfs_force_cow_block()\ndrops the last reference on the @buf extent buffer when it calls\nfree_extent_buffer_stale(buf), which schedules the release of the extent\nbuffer with RCU. This means that if we are on a kernel with preemption,\nthe current task may be preempted before calling trace_btrfs_cow_block()\nand the extent buffer already released by the time trace_btrfs_cow_block()\nis called, resulting in a use-after-free.\n\nFix this by moving the trace_btrfs_cow_block() from btrfs_cow_block() to\nbtrfs_force_cow_block() before the COWed extent buffer is freed.\nThis also has a side effect of invoking the tracepoint in the tree defrag\ncode, at defrag.c:btrfs_realloc_node(), since btrfs_force_cow_block() is\ncalled there, but this is fine and it was actually missing there."}],"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 code is btrfs's core b-tree COW path, reached through ordinary filesystem syscalls (write, create, unlink, rename) on a mounted btrfs volume. This requires local access to the system; there is no network protocol handler involved.\nAC:L - The attacker fully controls the triggering side — every metadata modification calls btrfs_search_slot() → btrfs_cow_block(), so the free-then-trace window can be retried millions of times, and the attacker can raise CPU/scheduling pressure with concurrent threads to make preemption at that point (and elapse of the RCU grace period) occur. A race the attacker can drive at will and retry unboundedly is Low complexity.\nPR:L - Only an unprivileged local account with write access to any btrfs filesystem is needed; no capability, CAP_SYS_ADMIN, or namespace check exists anywhere on the btrfs_search_slot() → btrfs_cow_block() path. Writing into a home directory or container rootfs on btrfs is sufficient.\nUI:N - The attacker triggers the COW path directly with its own filesystem operations; no victim action, mount, or file-open by another user is required.\nS:U - The use-after-free is confined to kernel memory managed by the same kernel security authority; there is no VM, IOMMU, or sandbox boundary crossed.\nC:H - The freed extent_buffer is read after release from a mergeable, non-TYPESAFE_BY_RCU slab cache, and btrfs_header_level(buf) loads eb->folios[0] and dereferences it — with heap spray this becomes a controlled-address read whose result is emitted into the trace ring buffer, disclosing kernel memory.\nI:H - The use-after-free on a reclaimable, slab-mergeable object gives the attacker influence over the contents of the reused allocation and the pointer subsequently dereferenced, which is the standard primitive for escalating a UAF into kernel memory corruption and control-flow hijacking.\nA:H - Dereferencing the freed extent_buffer and its stale folios[0] pointer causes a wild-pointer access that oopses or panics the kernel (this is exactly what syzbot's KASAN report captured), and it can be re-triggered repeatedly."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/btrfs/ctree.c"],"versions":[{"version":"3083ee2e18b701122a3b841db83448543a87a583","lessThan":"ba5120a2fb5f23b4d39d302e181aa5d4e28a90d1","status":"affected","versionType":"git"},{"version":"3083ee2e18b701122a3b841db83448543a87a583","lessThan":"526ff5b27f090fb15040471f892cd2c9899ce314","status":"affected","versionType":"git"},{"version":"3083ee2e18b701122a3b841db83448543a87a583","lessThan":"66376f1a73cba57fd0af2631d7888605b738e499","status":"affected","versionType":"git"},{"version":"3083ee2e18b701122a3b841db83448543a87a583","lessThan":"9a466b8693b9add05de99af00c7bdff8259ecf19","status":"affected","versionType":"git"},{"version":"3083ee2e18b701122a3b841db83448543a87a583","lessThan":"c3a403d8ce36f5a809a492581de5ad17843e4701","status":"affected","versionType":"git"},{"version":"3083ee2e18b701122a3b841db83448543a87a583","lessThan":"44f52bbe96dfdbe4aca3818a2534520082a07040","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/btrfs/ctree.c"],"versions":[{"version":"3.4","status":"affected"},{"version":"0","lessThan":"3.4","status":"unaffected","versionType":"semver"},{"version":"5.10.233","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.176","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.124","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.70","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.8","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.13","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":"3.4","versionEndExcluding":"5.10.233"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.4","versionEndExcluding":"5.15.176"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.4","versionEndExcluding":"6.1.124"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.4","versionEndExcluding":"6.6.70"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.4","versionEndExcluding":"6.12.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.4","versionEndExcluding":"6.13"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/ba5120a2fb5f23b4d39d302e181aa5d4e28a90d1"},{"url":"https://git.kernel.org/stable/c/526ff5b27f090fb15040471f892cd2c9899ce314"},{"url":"https://git.kernel.org/stable/c/66376f1a73cba57fd0af2631d7888605b738e499"},{"url":"https://git.kernel.org/stable/c/9a466b8693b9add05de99af00c7bdff8259ecf19"},{"url":"https://git.kernel.org/stable/c/c3a403d8ce36f5a809a492581de5ad17843e4701"},{"url":"https://git.kernel.org/stable/c/44f52bbe96dfdbe4aca3818a2534520082a07040"}],"title":"btrfs: fix use-after-free when COWing tree bock and tracing is enabled","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-2024-56759","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2025-02-11T15:41:24.236942Z"}}}],"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":"2025-02-11T15:45:20.928Z"}},{"title":"CVE Program Container","references":[{"url":"https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html"},{"url":"https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html"}],"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2025-11-03T20:53:52.637Z"}}]}}