CVE-2026-56099 json
OpenBSD mpls_do_error Kernel Stack Memory Disclosure via MPLS Input
published 2026-06-18 4 mo ago modified 2026-10-26 13 d ago also EUVD-2026-37938
- cvss
- 5.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 43%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- openbsd openbsd 2026-06-18
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 4 mo ago
Exploit prediction
0.50% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- pop.argus-systems.ai https://pop.argus-systems.ai/advisory/adv-040.html referenced PoC, tagged "exploit" by a source, unverified
- openwall.com http://www.openwall.com/lists/oss-security/2026/06/19/3 referenced PoC, tagged "exploit" by a source, unverified
- seclists.org http://seclists.org/fulldisclosure/2026/Jun/17 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 6.9 | 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 |
| CNA | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N |
| CNA | 4.0 | 6.9 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| NVD | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N |
Affected products
- openbsd src
Classification
- Weakness
-
- CWE-125 Out-of-bounds Read
References
-
github.com
/openbsd/src/commit/6a23123ec05f1eb29cfcaae0f3a468b2e1983cfd
patch
-
pop.argus-systems.ai
/advisory/adv-040.html
technical-description, exploit, patch, third-party-advisory
-
openwall.com
/lists/oss-security/2026/06/19/3
exploit, mailing-list, patch, third-party-advisory
-
seclists.org
/fulldisclosure/2026/Jun/17
exploit, mailing-list, patch, third-party-advisory
-
vulncheck.com
/advisories/openbsd-mpls-do-error-kernel-stack-memory-disclosure-via-mpls-input
third-party-advisory
Sources
- CVE List CVE-2026-56099
- NVD CVE-2026-56099
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