CVE-2026-43455 Affecting kernel-source package, versions <6.12.0-160000.35.1
Threat Intelligence
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Test your applications- Snyk IDSNYK-SLES1600-KERNELSOURCE-17355197
- published17 Jun 2026
- disclosed15 Jun 2026
Introduced: 15 Jun 2026
NewCVE-2026-43455 (opens in a new tab)How to fix?
Upgrade SLES:16.0.0 kernel-source to version 6.12.0-160000.35.1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-source package and not the kernel-source package as distributed by SLES.
See How to fix? for SLES:16.0.0 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
mctp: route: hold key->lock in mctp_flow_prepare_output()
mctp_flow_prepare_output() checks key->dev and may call mctp_dev_set_key(), but it does not hold key->lock while doing so.
mctp_dev_set_key() and mctp_dev_release_key() are annotated with __must_hold(&key->lock), so key->dev access is intended to be serialized by key->lock. The mctp_sendmsg() transmit path reaches mctp_flow_prepare_output() via mctp_local_output() -> mctp_dst_output() without holding key->lock, so the check-and-set sequence is racy.
Example interleaving:
CPU0 CPU1
mctp_flow_prepare_output(key, devA) if (!key->dev) // sees NULL mctp_flow_prepare_output( key, devB) if (!key->dev) // still NULL mctp_dev_set_key(devB, key) mctp_dev_hold(devB) key->dev = devB mctp_dev_set_key(devA, key) mctp_dev_hold(devA) key->dev = devA // overwrites devB
Now both devA and devB references were acquired, but only the final key->dev value is tracked for release. One reference can be lost, causing a resource leak as mctp_dev_release_key() would only decrease the reference on one dev.
Fix by taking key->lock around the key->dev check and mctp_dev_set_key() call.
References
- https://www.suse.com/security/cve/CVE-2026-43455.html
- https://bugzilla.suse.com/1264765
- https://git.kernel.org/stable/c/0695712f3a6f1a48915f95767cfb42077683dcdc
- https://git.kernel.org/stable/c/47893166bc5611ee9a20de6b8d2933b2320fb772
- https://git.kernel.org/stable/c/7d86aa41c073c4e7eb75fd2e674f1fd8f289728a
- https://git.kernel.org/stable/c/86f5334fcb48a5b611c33364ab52ca684d0f6d91
- https://git.kernel.org/stable/c/8d27d9b260dd19c1b519e1a13de6448f9984e30e
- https://git.kernel.org/stable/c/925a5ffd99cddd7a7e41d5ad120c7a2c6d50260f