{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-38614","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-04-16T04:51:24.029Z","datePublished":"2025-08-19T17:03:56.348Z","dateUpdated":"2026-08-05T12:03:29.308Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:03:29.308Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\neventpoll: Fix semi-unbounded recursion\n\nEnsure that epoll instances can never form a graph deeper than\nEP_MAX_NESTS+1 links.\n\nCurrently, ep_loop_check_proc() ensures that the graph is loop-free and\ndoes some recursion depth checks, but those recursion depth checks don't\nlimit the depth of the resulting tree for two reasons:\n\n - They don't look upwards in the tree.\n - If there are multiple downwards paths of different lengths, only one of\n   the paths is actually considered for the depth check since commit\n   28d82dc1c4ed (\"epoll: limit paths\").\n\nEssentially, the current recursion depth check in ep_loop_check_proc() just\nserves to prevent it from recursing too deeply while checking for loops.\n\nA more thorough check is done in reverse_path_check() after the new graph\nedge has already been created; this checks, among other things, that no\npaths going upwards from any non-epoll file with a length of more than 5\nedges exist. However, this check does not apply to non-epoll files.\n\nAs a result, it is possible to recurse to a depth of at least roughly 500,\ntested on v6.15. (I am unsure if deeper recursion is possible; and this may\nhave changed with commit 8c44dac8add7 (\"eventpoll: Fix priority inversion\nproblem\").)\n\nTo fix it:\n\n1. In ep_loop_check_proc(), note the subtree depth of each visited node,\nand use subtree depths for the total depth calculation even when a subtree\nhas already been visited.\n2. Add ep_get_upwards_depth_proc() for similarly determining the maximum\ndepth of an upwards walk.\n3. In ep_loop_check(), use these values to limit the total path length\nbetween epoll nodes to EP_MAX_NESTS edges."}],"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 vulnerability is reached exclusively through the local epoll syscall interface (epoll_create/epoll_ctl/epoll_wait); there is no network-reachable path to build or trigger the nested epoll graph.\nAC:L - The attacker fully controls construction of the deep epoll chain via EPOLL_CTL_ADD and deterministically triggers the recursive walk; no race or uncontrolled condition is involved.\nPR:L - Any unprivileged local user can create and nest epoll instances and invoke poll/epoll_wait — no capabilities, root, or namespaces are required.\nUI:N - The attacker performs every step (nesting the fds and triggering the recursion) alone; no victim action is needed.\nS:U - The stack overflow corrupts kernel memory within the same security authority (the kernel); it does not cross a VM/IOMMU/sandbox boundary.\nC:H - On configs without VMAP_STACK guard pages (32-bit ARM, embedded, older kernels in the affected range), the recursion overflows the kernel stack into adjacent kernel memory, a corruption that can be leveraged to disclose kernel memory.\nI:H - The kernel-stack overflow overwrites adjacent kernel structures (historically thread_info/addr_limit), providing a memory-corruption primitive that can be steered toward control-flow hijack and arbitrary write.\nA:H - The semi-unbounded recursion reliably exhausts the 8–16KB kernel stack, causing a guard-page panic or oops and taking down the entire system."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/eventpoll.c"],"versions":[{"version":"22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e","lessThan":"71379495ab70eaba19224bd71b5b9b399eb85e04","status":"affected","versionType":"git"},{"version":"22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e","lessThan":"1b13b033062824495554e836a1ff5f85ccf6b039","status":"affected","versionType":"git"},{"version":"22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e","lessThan":"2a0c0c974bea9619c6f41794775ae4b97530e0e6","status":"affected","versionType":"git"},{"version":"22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e","lessThan":"7a2125962c42d5336ca0495a9ce4cb38a63e9161","status":"affected","versionType":"git"},{"version":"22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e","lessThan":"ea5f97dbdcb1651581a22bd10afd2f0dd9dc11d6","status":"affected","versionType":"git"},{"version":"22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e","lessThan":"3542c90797bc3ab83ebab54b737d751cf3682036","status":"affected","versionType":"git"},{"version":"22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e","lessThan":"f2e467a48287c868818085aa35389a224d226732","status":"affected","versionType":"git"},{"version":"8216e1a0d47cae06a75c42346f19dffe14e42d57","status":"affected","versionType":"git"},{"version":"28a92748aa4bc57d35e7b079498b0ac2e7610a37","status":"affected","versionType":"git"},{"version":"7eebcd4792c5a341559aed327b6afecbb1c46402","status":"affected","versionType":"git"},{"version":"0eccd188cfeaf857a26f2d72941d27d298cf6a54","status":"affected","versionType":"git"},{"version":"a72affdbb09f3f24f64ffcbbdf62c2e57c58f379","status":"affected","versionType":"git"},{"version":"2.6.32.30","lessThan":"2.6.33","status":"affected","versionType":"semver"},{"version":"2.6.33.8","lessThan":"2.6.34","status":"affected","versionType":"semver"},{"version":"2.6.34.10","lessThan":"2.6.35","status":"affected","versionType":"semver"},{"version":"2.6.35.12","lessThan":"2.6.36","status":"affected","versionType":"semver"},{"version":"2.6.37.3","lessThan":"2.6.38","status":"affected","versionType":"semver"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/eventpoll.c"],"versions":[{"version":"2.6.38","status":"affected"},{"version":"0","lessThan":"2.6.38","status":"unaffected","versionType":"semver"},{"version":"5.15.190","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.149","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.103","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.43","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.15.11","lessThanOrEqual":"6.15.*","status":"unaffected","versionType":"semver"},{"version":"6.16.1","lessThanOrEqual":"6.16.*","status":"unaffected","versionType":"semver"},{"version":"6.17","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":"2.6.38","versionEndExcluding":"5.15.190"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.38","versionEndExcluding":"6.1.149"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.38","versionEndExcluding":"6.6.103"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.38","versionEndExcluding":"6.12.43"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.38","versionEndExcluding":"6.15.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.38","versionEndExcluding":"6.16.1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.38","versionEndExcluding":"6.17"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.32.30"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.33.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.35.12"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.37.3"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/71379495ab70eaba19224bd71b5b9b399eb85e04"},{"url":"https://git.kernel.org/stable/c/1b13b033062824495554e836a1ff5f85ccf6b039"},{"url":"https://git.kernel.org/stable/c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