CVE-2026-56099

medium

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.

References

https://www.vulncheck.com/advisories/openbsd-mpls-do-error-kernel-stack-memory-disclosure-via-mpls-input

https://pop.argus-systems.ai/advisory/adv-040.html

https://github.com/openbsd/src/commit/6a23123ec05f1eb29cfcaae0f3a468b2e1983cfd

Details

Source: Mitre, NVD

Published: 2026-06-18

Updated: 2026-06-27

Risk Information

CVSS v2

Base Score: 5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:N

Severity: Medium

CVSS v3

Base Score: 5.3

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Severity: Medium

CVSS v4

Base Score: 6.9

Vector: 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

Severity: Medium

EPSS

EPSS: 0.00356