mpls: add seqcount to protect the platform_label{,s} pair
CVE-2026-43042 · published 1 May 2026
How serious is it
- Severity: high, CVSS score 7.1 out of 10.
- No exploit prediction (EPSS) score yet.
- Not on the CISA list of exploited vulnerabilities.
- No public exploit in Exploit-DB.
Is your app affected by CVE-2026-43042?
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Who is affected
- Linux Linux: 7720c01f3f590116882e251f13c7e1d5602f8643 to < 0d377825548fe598595b5a5fa4a309fb593d8fb4, 7720c01f3f590116882e251f13c7e1d5602f8643 to < 8adc5b6fc876928d8c95555d30b66fa50b07421e, 7720c01f3f590116882e251f13c7e1d5602f8643 to < 5bb3caf0bbfb56f1a00d2af072ac3d8395a3b9ef, 7720c01f3f590116882e251f13c7e1d5602f8643 to < 629ec78ef8608d955ce217880cdc3e1873af3a15
- Linux Linux: 4.1
How to check
- Find out whether you run the affected product and which version, then compare it with the versions above.
How to fix
Copies a prompt for Claude Code, Cursor or Codex that asks it to check whether you run this product.
- Apply the vendor's update or mitigation from the references below. If there is none yet, limit exposure of the affected service until there is.
- If a vulnerable version was live, check your logs and rotate the secrets that server could read.
The advisory
In the Linux kernel, the following vulnerability has been resolved:
mpls: add seqcount to protect the platform_label{,s} pair
The RCU-protected codepaths (mpls_forward, mpls_dump_routes) can have
an inconsistent view of platform_labels vs platform_label in case of a
concurrent resize (resize_platform_label_table, under
platform_mutex). This can lead to OOB accesses.
This patch adds a seqcount, so that we get a consistent snapshot.
Note that mpls_label_ok is also susceptible to this, so the check
against RTA_DST in rtm_to_route_config, done outside platform_mutex,
is not sufficient. This value gets passed to mpls_label_ok once more
in both mpls_route_add and mpls_route_del, so there is no issue, but
that additional check must not be removed.
Check your whole app
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References
- git.kernel.org/stable/c/0d377825548fe598595b5a5fa4a309fb593d8fb4
- git.kernel.org/stable/c/8adc5b6fc876928d8c95555d30b66fa50b07421e
- git.kernel.org/stable/c/5bb3caf0bbfb56f1a00d2af072ac3d8395a3b9ef
- git.kernel.org/stable/c/629ec78ef8608d955ce217880cdc3e1873af3a15
Merged from CVE List. Last updated 25 Oct 2026. All vulnerabilities · RSS · JSON