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CVE-2026-56099

OpenBSD mpls_do_error Kernel Stack Memory Disclosure via MPLS Input

Published: Jun 18, 2026Updated: Jun 22, 2026 Sources: CVE List NVDCWE-125
NVD MITRE
5.3CVSSMEDIUM
EPSS Score
N/A
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available

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 Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:LI:NA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:LConfidentiality
Low
I:NIntegrity
None
A:NAvailability
None
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Weaknesses

CWE-125

Affected Products

srcopenbsd
On-prem
Operating Systems / unix-bsd
openbsdoss-projectCAOperating Systemsaka openbsd

Attack Graph

Products CVE Techniques Tactics

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Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

MITRE ATT&CK

1 technique
Collection
View detailed technique mapping

References

https://pop.argus-systems.ai/advisory/adv-040.html
pop.argus-systems.ai
https://github.com/openbsd/src/commit/6a23123ec05f1eb29cfcaae0f3a468b2e1983cfd
github.com
https://www.vulncheck.com/advisories/openbsd-mpls-do-error-kernel-stack-memory-disclosure-via-mpls-input
vulncheck.com
and 2 more references View all →

Timeline

Published
Jun 18, 2026
Last Updated
Jun 22, 2026

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