{"cve":"CVE-2026-43388","nvd":{"published":"2026-05-08T15:16:50.180","modified":"2026-06-17T10:49:30.320","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/damon/core: clear walk_control on inactive context in damos_walk()\n\ndamos_walk() sets ctx->walk_control to the caller-provided control\nstructure before checking whether the context is running.  If the context\nis inactive (damon_is_running() returns false), the function returns\n-EINVAL without clearing ctx->walk_control.  This leaves a dangling\npointer to a stack-allocated structure that will be freed when the caller\nreturns.\n\nThis is structurally identical to the bug fixed in commit f9132fbc2e83\n(\"mm/damon/core: remove call_control in inactive contexts\") for\ndamon_call(), which had the same pattern of linking a control object and\nreturning an error without unlinking it.\n\nThe dangling walk_control pointer can cause:\n1. Use-after-free if the context is later started and kdamond\n   dereferences ctx->walk_control (e.g., in damos_walk_cancel()\n   which writes to control->canceled and calls complete())\n2. Permanent -EBUSY from subsequent damos_walk() calls, since the\n   stale pointer is non-NULL\n\nNonetheless, the real user impact is quite restrictive.  The\nuse-after-free is impossible because there is no damos_walk() callers who\nstarts the context later.  The permanent -EBUSY can actually confuse\nusers, as DAMON is not running.  But the symptom is kept only while the\ncontext is turned off.  Turning it on again will make DAMON internally\nuses a newly generated damon_ctx object that doesn't have the invalid\ndamos_walk_control pointer, so everything will work fine again.\n\nFix this by clearing ctx->walk_control under walk_control_lock before\nreturning -EINVAL, mirroring the fix pattern from f9132fbc2e83.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":["CWE-416"],"references":["https://git.kernel.org/stable/c/9320c77134ab8d7701e20608bbf08517df4fa321","https://git.kernel.org/stable/c/ce0aa47c963b8c3e5beace89e2b5a665a64b5b6b","https://git.kernel.org/stable/c/d210fdcac9c0d1380eab448aebc93f602c1cd4e6"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:33:55.586217763+00:00"},"epss":{"cve":"CVE-2026-43388","score":0.00124,"percentile":0.02091,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}