{"id":"CVE-2026-23437","state":"PUBLISHED","title":"net: shaper: protect late read accesses to the hierarchy","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: shaper: protect late read accesses to the hierarchy\n\nWe look up a netdev during prep of Netlink ops (pre- callbacks)\nand take a ref to it. Then later in the body of the callback\nwe take its lock or RCU which are the actual protections.\n\nThis is not proper, a conversion from a ref to a locked netdev\nmust include a liveness check (a check if the netdev hasn't been\nunregistered already). Fix the read cases (those under RCU).\nWrites needs a separate change to protect from creating the\nhierarchy after flush has already run.","publishedAt":"2026-04-03T15:15:22.048Z","updatedAt":"2026-10-19T18:35:43.629Z","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":"4b623f9f0f59652ea71fcb27d60b4c3b65126dbb","status":"affected","lessThan":"581eee0890a8bde44f1fb78ad3e70502a897d583","versionType":"git"},{"version":"4b623f9f0f59652ea71fcb27d60b4c3b65126dbb","status":"affected","lessThan":"348758ba74e6a348299965b16a97cfb817545cc0","versionType":"git"},{"version":"4b623f9f0f59652ea71fcb27d60b4c3b65126dbb","status":"affected","lessThan":"0f9ea7141f365b4f27226898e62220fb98ef8dc6","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/shaper/shaper.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.13","versionType":"semver"},{"version":"6.18.20","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.10","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":["net/shaper/shaper.c"]}],"references":["https://git.kernel.org/stable/c/581eee0890a8bde44f1fb78ad3e70502a897d583","https://git.kernel.org/stable/c/348758ba74e6a348299965b16a97cfb817545cc0","https://git.kernel.org/stable/c/0f9ea7141f365b4f27226898e62220fb98ef8dc6"],"weaknesses":["CWE-662"],"ingestedAt":"2026-10-29T20:11:21.040Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/23xxx/CVE-2026-23437.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-23437","state":"PUBLISHED","datePublished":"2026-04-03T15:15:22.048Z","dateUpdated":"2026-10-19T18:35:43.629Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-01-13T15:37:46.017Z"},"containers":{"cna":{"title":"net: shaper: protect late read accesses to the hierarchy","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: shaper: protect late read accesses to the hierarchy\n\nWe look up a netdev during prep of Netlink ops (pre- callbacks)\nand take a ref to it. Then later in the body of the callback\nwe take its lock or RCU which are the actual protections.\n\nThis is not proper, a conversion from a ref to a locked netdev\nmust include a liveness check (a check if the netdev hasn't been\nunregistered already). Fix the read cases (those under RCU).\nWrites needs a separate change to protect from creating the\nhierarchy after flush has already run."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"4b623f9f0f59652ea71fcb27d60b4c3b65126dbb","status":"affected","lessThan":"581eee0890a8bde44f1fb78ad3e70502a897d583","versionType":"git"},{"version":"4b623f9f0f59652ea71fcb27d60b4c3b65126dbb","status":"affected","lessThan":"348758ba74e6a348299965b16a97cfb817545cc0","versionType":"git"},{"version":"4b623f9f0f59652ea71fcb27d60b4c3b65126dbb","status":"affected","lessThan":"0f9ea7141f365b4f27226898e62220fb98ef8dc6","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/shaper/shaper.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.13","versionType":"semver"},{"version":"6.18.20","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.10","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":["net/shaper/shaper.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/581eee0890a8bde44f1fb78ad3e70502a897d583"},{"url":"https://git.kernel.org/stable/c/348758ba74e6a348299965b16a97cfb817545cc0"},{"url":"https://git.kernel.org/stable/c/0f9ea7141f365b4f27226898e62220fb98ef8dc6"}],"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 reached through local Generic Netlink `net-shaper` requests, not by remote network packets.\nAC:L - This is a race, but a local attacker can repeatedly issue read requests while causing or waiting for netdevice teardown; the vulnerable window is directly exercised by concurrent Netlink/device-lifetime activity.\nPR:L - The affected `GET` and dump read paths do not require `GENL_ADMIN_PERM`; a basic local user can open a Generic Netlink socket and issue these requests.\nUI:N - No victim user action is required once the attacker can send the Netlink requests.\nS:U - The bug affects kernel networking state within the same kernel security authority and does not cross a VM, IOMMU, or comparable boundary.\nC:H - The bug is a use-after-free of the net shaper hierarchy/shaper objects, and freed kernel heap contents may be exposed or shaped into useful read primitives.\nI:H - Use-after-free of kernel heap objects is memory corruption and may be exploitable through heap reuse for control-flow or data corruption.\nA:H - The stale hierarchy pointer can be dereferenced after teardown, making kernel oops/panic or other denial of service likely."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:21:45.565Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"6.18.20"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"6.19.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"7.0"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-23437","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:08:04.357382Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-662","lang":"en","type":"CWE","description":"CWE-662 Improper Synchronization"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T18:35:43.629Z"}}]}}}