CVE-2026-56099
OpenBSD mpls_do_error Kernel Stack Memory Disclosure via MPLS Input
- State
- Published
- Severity
- 6.9 Medium
- Published
- Jun 18, 2026
- Updated
- Jul 14, 2026
- Reserved
- Jun 18, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 6.9 Medium | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 5.3 Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N | VulnCheck |
Weaknesses
- CWE-125 Out-of-bounds Read
Affected Products
| Product | Versions |
|---|---|
srcopenbsd |
|
References
- https://pop.argus-systems.ai/advisory/adv-040.htmltechnical-descriptionexploit
- https://github.com/openbsd/src/commit/6a23123ec05f1eb29cfcaae0f3a468b2e1983cfdpatch
- https://www.vulncheck.com/advisories/openbsd-mpls-do-error-kernel-stack-memory-disclosure-via-mpls-inputthird-party-advisory
- http://www.openwall.com/lists/oss-security/2026/06/19/3
- http://seclists.org/fulldisclosure/2026/Jun/17
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