{"id":"CVE-2026-80995","title":"net: mctp: hold a reference to the route device in mctp_route_lookup()","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: mctp: hold a reference to the route device in mctp_route_lookup()\n\nmctp_route_lookup() uses rt->dev without holding a reference on it.\nmctp_route_lookup_single() r…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","cwe":["CWE-825"],"vendor":"Linux","product":"Linux","affected":["Linux >= 22cb45afd221b9e4f2a1dcc74a8ff645b7293aa1 < cc561f8af25586300c2f9d285babb163b866b293","Linux >= 22cb45afd221b9e4f2a1dcc74a8ff645b7293aa1 < 408da1df18116c971c3392e21e50586688cd3fbf","Linux 7.1"],"published":"2026-09-11","updated":"2026-10-19","sourceUpdated":"2026-10-19T08:46:19.571Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-80995","references":[{"url":"https://git.kernel.org/stable/c/cc561f8af25586300c2f9d285babb163b866b293"},{"url":"https://git.kernel.org/stable/c/408da1df18116c971c3392e21e50586688cd3fbf"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80995.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-80995"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532081"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-80995"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80995"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-80995.mbox"}],"tags":["cve.org","csaf","vex","red-hat","score-dispute"],"epss":0.00165,"epssPercentile":0.05669,"scores":{"cna":7.8,"vendor":5.5},"ingestedAt":"2026-09-14T15:23:07.476Z","slug":"CVE-2026-80995","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet: mctp: hold a reference to the route device in mctp_route_lookup()\n\nmctp_route_lookup() uses rt->dev without holding a reference on it.\nmctp_route_lookup_single() returns the route under RCU only, so the\nroute's device can be torn down concurrently: mctp_dev_put() drops the\nlast reference and synchronously kfree()s mdev->addrs.  mctp_dev_saddr()\nthen reads rt->dev->addrs[0], giving a use-after-free reachable by an\nunprivileged local AF_MCTP user on the receive/forwarding path (no\nCAP_NET_RAW required):\n\n  BUG: KASAN: slab-use-after-free in mctp_route_lookup\n  Read of size 1 at addr ... by task mctp_uaf/...\n   mctp_route_lookup\n   mctp_pkttype_receive\n  Freed by task ...:\n   kfree\n   mctp_dev_put\n   mctp_dev_notify\n\nIn the same window mctp_dst_from_route() -> mctp_dev_hold() also\nincrements a refcount that has already reached zero\n(\"refcount_t: addition on 0 ... mctp_dev_hold\").\n\nThis reintroduces the use-after-free class of CVE-2023-3439: the source\naddress lookup was moved ahead of the point where the destination takes\nits device reference.\n\nTake a reference with refcount_inc_not_zero() before touching rt->dev,\nskip a device that is already dead, and drop the reference once the\ndestination has taken its own.\n\n## Affected\n\n- `Linux >= 22cb45afd221b9e4f2a1dcc74a8ff645b7293aa1 < cc561f8af25586300c2f9d285babb163b866b293`\n- `Linux >= 22cb45afd221b9e4f2a1dcc74a8ff645b7293aa1 < 408da1df18116c971c3392e21e50586688cd3fbf`\n- `Linux 7.1`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · updated 2026-09-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80995.json)","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":224784,"id":"CVE-2026-80995","ts":1792401541459,"field":"cvss","old":"5.5","new":"7.8"},{"seq":224783,"id":"CVE-2026-80995","ts":1792401541459,"field":"severity","old":"medium","new":"high"},{"seq":204150,"id":"CVE-2026-80995","ts":1789490233122,"field":"cvss","old":"4.7","new":"5.5"},{"seq":202925,"id":"CVE-2026-80995","ts":1789403732974,"field":"cvss","old":"7.8","new":"4.7"},{"seq":202924,"id":"CVE-2026-80995","ts":1789403732974,"field":"severity","old":"high","new":"medium"},{"seq":183578,"id":"CVE-2026-80995","ts":1789356675960,"field":"cvss","old":"7.8","new":"4.7"},{"seq":183577,"id":"CVE-2026-80995","ts":1789356675960,"field":"severity","old":"high","new":"medium"},{"seq":153184,"id":"CVE-2026-80995","ts":1789285349451,"field":"cvss","old":null,"new":"7.8"},{"seq":153183,"id":"CVE-2026-80995","ts":1789285349451,"field":"severity","old":"none","new":"high"},{"seq":109574,"id":"CVE-2026-80995","ts":1789183732471,"field":"cvss","old":null,"new":"4.7"},{"seq":109573,"id":"CVE-2026-80995","ts":1789183732471,"field":"severity","old":"none","new":"medium"}]}