CVE-2026-80995
net: mctp: hold a reference to the route device in mctp_route_lookup()
Description
In the Linux kernel, the following vulnerability has been resolved: net: mctp: hold a reference to the route device in mctp_route_lookup() mctp_route_lookup() uses rt->dev without holding a reference on it. mctp_route_lookup_single() returns the route under RCU only, so the route's device can be torn down concurrently: mctp_dev_put() drops the last reference and synchronously kfree()s mdev->addrs. mctp_dev_saddr() then reads rt->dev->addrs[0], giving a use-after-free reachable by an unprivileged local AF_MCTP user on the receive/forwarding path (no CAP_NET_RAW required): BUG: KASAN: slab-use-after-free in mctp_route_lookup Read of size 1 at addr ... by task mctp_uaf/... mctp_route_lookup mctp_pkttype_receive Freed by task ...: kfree mctp_dev_put mctp_dev_notify In the same window mctp_dst_from_route() -> mctp_dev_hold() also increments a refcount that has already reached zero ("refcount_t: addition on 0 ... mctp_dev_hold"). This reintroduces the use-after-free class of CVE-2023-3439: the source address lookup was moved ahead of the point where the destination takes its device reference. Take a reference with refcount_inc_not_zero() before touching rt->dev, skip a device that is already dead, and drop the reference once the destination has taken its own.
INFO
Published Date :
Sept. 11, 2026, 8:19 p.m.
Last Modified :
Sept. 13, 2026, 7:17 a.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
- Take a reference before touching the route device.
- Skip dead devices.
- Drop the reference after destination takes its own.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-80995.
| URL | Resource |
|---|---|
| https://git.kernel.org/stable/c/408da1df18116c971c3392e21e50586688cd3fbf | |
| https://git.kernel.org/stable/c/cc561f8af25586300c2f9d285babb163b866b293 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-80995 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-80995
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-80995 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-80995 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 13, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 11, 2026
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: net: mctp: hold a reference to the route device in mctp_route_lookup() mctp_route_lookup() uses rt->dev without holding a reference on it. mctp_route_lookup_single() returns the route under RCU only, so the route's device can be torn down concurrently: mctp_dev_put() drops the last reference and synchronously kfree()s mdev->addrs. mctp_dev_saddr() then reads rt->dev->addrs[0], giving a use-after-free reachable by an unprivileged local AF_MCTP user on the receive/forwarding path (no CAP_NET_RAW required): BUG: KASAN: slab-use-after-free in mctp_route_lookup Read of size 1 at addr ... by task mctp_uaf/... mctp_route_lookup mctp_pkttype_receive Freed by task ...: kfree mctp_dev_put mctp_dev_notify In the same window mctp_dst_from_route() -> mctp_dev_hold() also increments a refcount that has already reached zero ("refcount_t: addition on 0 ... mctp_dev_hold"). This reintroduces the use-after-free class of CVE-2023-3439: the source address lookup was moved ahead of the point where the destination takes its device reference. Take a reference with refcount_inc_not_zero() before touching rt->dev, skip a device that is already dead, and drop the reference once the destination has taken its own. Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/80xxx/CVE-2026-80995.json">CVE-2026-80995</a> Added Reference https://git.kernel.org/stable/c/408da1df18116c971c3392e21e50586688cd3fbf Added Reference https://git.kernel.org/stable/c/cc561f8af25586300c2f9d285babb163b866b293