{"id":"CVE-2026-43074","state":"PUBLISHED","title":"eventpoll: defer struct eventpoll free to RCU grace period","description":"In the Linux kernel, the following vulnerability has been resolved:\n\neventpoll: defer struct eventpoll free to RCU grace period\n\nIn certain situations, ep_free() in eventpoll.c will kfree the epi->ep\neventpoll struct while it still being used by another concurrent thread.\nDefer the kfree() to an RCU callback to prevent UAF.","publishedAt":"2026-05-06T07:21:58.210Z","updatedAt":"2026-10-19T19:06:12.716Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"f2451def095c1743adcfcb0cb5dadc86034e162a","status":"affected","lessThan":"902120be4f44947df6311002addc7faf69bdbff1","versionType":"git"},{"version":"a1f93804449d13f97dabd4b996817de4bf1ed67a","status":"affected","lessThan":"a6d57084372161f86660bc4607784420e00efe2c","versionType":"git"},{"version":"58c9b016e12855286370dfb704c08498edbc857a","status":"affected","lessThan":"a6566cd33f6f967a7651ebf2ce0dd31572e319cf","versionType":"git"},{"version":"58c9b016e12855286370dfb704c08498edbc857a","status":"affected","lessThan":"5b1173b165421561db29f30afc7e97d940a398a9","versionType":"git"},{"version":"58c9b016e12855286370dfb704c08498edbc857a","status":"affected","lessThan":"7e8083f5eeedab0f460063b9c2c14c9a4e71a427","versionType":"git"},{"version":"58c9b016e12855286370dfb704c08498edbc857a","status":"affected","lessThan":"ae0bb9c1fb7c2594519aeeb096cf2c3b7837b322","versionType":"git"},{"version":"58c9b016e12855286370dfb704c08498edbc857a","status":"affected","lessThan":"07712db80857d5d09ae08f3df85a708ecfc3b61f","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/eventpoll.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.4","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.4","versionType":"semver"},{"version":"6.6.136","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.83","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.24","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.14","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/eventpoll.c"]}],"references":["https://git.kernel.org/stable/c/902120be4f44947df6311002addc7faf69bdbff1","https://git.kernel.org/stable/c/a6d57084372161f86660bc4607784420e00efe2c","https://git.kernel.org/stable/c/a6566cd33f6f967a7651ebf2ce0dd31572e319cf","https://git.kernel.org/stable/c/5b1173b165421561db29f30afc7e97d940a398a9","https://git.kernel.org/stable/c/7e8083f5eeedab0f460063b9c2c14c9a4e71a427","https://git.kernel.org/stable/c/ae0bb9c1fb7c2594519aeeb096cf2c3b7837b322","https://git.kernel.org/stable/c/07712db80857d5d09ae08f3df85a708ecfc3b61f","https://cert-portal.siemens.com/productcert/html/ssa-784472.html"],"weaknesses":["CWE-416"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/43xxx/CVE-2026-43074.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-43074","state":"PUBLISHED","datePublished":"2026-05-06T07:21:58.210Z","dateUpdated":"2026-10-19T19:06:12.716Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-05-01T14:12:55.982Z"},"containers":{"cna":{"title":"eventpoll: defer struct eventpoll free to RCU grace period","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\neventpoll: defer struct eventpoll free to RCU grace period\n\nIn certain situations, ep_free() in eventpoll.c will kfree the epi->ep\neventpoll struct while it still being used by another concurrent thread.\nDefer the kfree() to an RCU callback to prevent UAF."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"f2451def095c1743adcfcb0cb5dadc86034e162a","status":"affected","lessThan":"902120be4f44947df6311002addc7faf69bdbff1","versionType":"git"},{"version":"a1f93804449d13f97dabd4b996817de4bf1ed67a","status":"affected","lessThan":"a6d57084372161f86660bc4607784420e00efe2c","versionType":"git"},{"version":"58c9b016e12855286370dfb704c08498edbc857a","status":"affected","lessThan":"a6566cd33f6f967a7651ebf2ce0dd31572e319cf","versionType":"git"},{"version":"58c9b016e12855286370dfb704c08498edbc857a","status":"affected","lessThan":"5b1173b165421561db29f30afc7e97d940a398a9","versionType":"git"},{"version":"58c9b016e12855286370dfb704c08498edbc857a","status":"affected","lessThan":"7e8083f5eeedab0f460063b9c2c14c9a4e71a427","versionType":"git"},{"version":"58c9b016e12855286370dfb704c08498edbc857a","status":"affected","lessThan":"ae0bb9c1fb7c2594519aeeb096cf2c3b7837b322","versionType":"git"},{"version":"58c9b016e12855286370dfb704c08498edbc857a","status":"affected","lessThan":"07712db80857d5d09ae08f3df85a708ecfc3b61f","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/eventpoll.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.4","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.4","versionType":"semver"},{"version":"6.6.136","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.83","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.24","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.14","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/eventpoll.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/902120be4f44947df6311002addc7faf69bdbff1"},{"url":"https://git.kernel.org/stable/c/a6d57084372161f86660bc4607784420e00efe2c"},{"url":"https://git.kernel.org/stable/c/a6566cd33f6f967a7651ebf2ce0dd31572e319cf"},{"url":"https://git.kernel.org/stable/c/5b1173b165421561db29f30afc7e97d940a398a9"},{"url":"https://git.kernel.org/stable/c/7e8083f5eeedab0f460063b9c2c14c9a4e71a427"},{"url":"https://git.kernel.org/stable/c/ae0bb9c1fb7c2594519aeeb096cf2c3b7837b322"},{"url":"https://git.kernel.org/stable/c/07712db80857d5d09ae08f3df85a708ecfc3b61f"}],"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 path is reached through local epoll syscalls, primarily `epoll_ctl(EPOLL_CTL_ADD)` on nested epoll descriptors racing with descriptor close/release. Network input is not sufficient to reach the lifetime bug without local control of epoll file descriptors.\nAC:L - The race is attacker-controlled: an unprivileged local process can create the epoll graph and run concurrent threads performing nested `epoll_ctl()` and close/release operations. No rare external state or victim timing is required beyond winning a race the attacker can repeatedly drive.\nPR:L - Creating epoll descriptors and calling `epoll_ctl()` require only ordinary local user privileges. No capability check gates the vulnerable nested epoll path; the only capability-related logic masks `EPOLLWAKEUP` and is not relevant.\nUI:N - Exploitation does not require another user to open files, mount anything, or perform any action. The attacking process can create, nest, and close all relevant descriptors itself.\nS:U - The impact is within the kernel security authority as a local kernel memory corruption or privilege escalation. There is no VM escape, IOMMU bypass, or cross-authority boundary change shown by this bug.\nC:H - This is a use-after-free of `struct eventpoll` during an RCU walk, and the stale pointer can be dereferenced after the object is freed and potentially reallocated. Per kernel CVSS guidance, a UAF is treated as enabling high confidentiality impact through exploitable memory corruption.\nI:H - The stale `struct eventpoll` is not only read but also written via fields such as `gen` and `loop_check_depth` after free, making heap corruption plausible if the memory is reallocated. Per kernel CVSS guidance, UAF memory corruption supports high integrity impact.\nA:H - At minimum, dereferencing or writing a freed `struct eventpoll` can crash or corrupt the kernel. A local attacker can repeatedly trigger the race, so availability impact is high."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:25:45.708Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"6.6.136"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"6.12.83"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"6.18.24"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"6.19.14"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"7.0"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"affected":[{"vendor":"Siemens","product":"SIMATIC S7-1500 TM MFP - GNU/Linux subsystem","defaultStatus":"unknown","versions":[{"version":"0","status":"affected","lessThan":"*","versionType":"custom"}]}],"references":[{"url":"https://cert-portal.siemens.com/productcert/html/ssa-784472.html"}],"providerMetadata":{"shortName":"siemens-SADP","orgId":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e","dateUpdated":"2026-10-15T01:18:59.733Z"},"x_adpType":"supplier"},{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-43074","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:14:21.825973Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-416","lang":"en","type":"CWE","description":"CWE-416 Use After Free"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T19:06:12.716Z"}}]}}}