Vulnerability Description
OpenBSD before commit 6a23123 (2026-06-18) contains an out-of-bounds read vulnerability in the mpls_do_error function within sys/netmpls/mpls_input.c that allows remote attackers to disclose kernel stack memory by sending crafted MPLS frames with 16 labels and no Bottom-of-Stack bit set.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Openbsd | Openbsd | < 2026-06-18 |
Related Weaknesses (CWE)
References
- https://github.com/openbsd/src/commit/6a23123ec05f1eb29cfcaae0f3a468b2e1983cfdPatch
- https://pop.argus-systems.ai/advisory/adv-040.htmlExploitPatchThird Party Advisory
- https://www.vulncheck.com/advisories/openbsd-mpls-do-error-kernel-stack-memory-dThird Party Advisory
- http://seclists.org/fulldisclosure/2026/Jun/17ExploitMailing ListPatch
- http://www.openwall.com/lists/oss-security/2026/06/19/3ExploitMailing ListPatch
FAQ
What is CVE-2026-56099?
CVE-2026-56099 is a vulnerability with a CVSS score of 5.3 (MEDIUM). OpenBSD before commit 6a23123 (2026-06-18) contains an out-of-bounds read vulnerability in the mpls_do_error function within sys/netmpls/mpls_input.c that allows remote attackers to disclose kernel st...
How severe is CVE-2026-56099?
CVE-2026-56099 has been rated MEDIUM with a CVSS base score of 5.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-56099?
Check the references section above for vendor advisories and patch information. Affected products include: Openbsd Openbsd.