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TI-2026-40489 Aliases CVE-2026-56099GHSA-6qv5-f6m3-44g8

OpenBSD mpls_do_error Kernel Stack Memory Disclosure via MPLS Input

Priority LOW 37CWE-125Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Information disclosure
Confidentiality · integrity · availability
Low · None · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-125 and the CVSS impact.

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.005 43rd percentileScored 2026-11-07
Public exploit Yes 3 exploit referencesTagged by the CNA and NVD
Fix Fixed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

No affected products listed by the sources yet.

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:o:openbsd:openbsd:*:*:*:*:*:*:*:*before 2026-06-18VulnerableOpenBSD
  • cpe:2.3:o:openbsd:openbsd:*:*:*:*:*:*:*:* Versions before 2026-06-18 Vulnerable ·OpenBSD

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-56099
  2. 2026-10-03 Alias added: GHSA-6qv5-f6m3-44g8

References

Exploit 3

Patch 1

  • TI-2002-00376 Integer overflow in xdr_array function in RPC servers for operating systems that use… CVSS 3.1CRITICAL 9.8
  • TI-2003-00437 Off-by-one error in the fb_realpath() function, as derived from the realpath function in… CVSS 3.1CRITICAL 9.8
  • TI-2007-05153 Stack-based buffer overflow in the cons_options function in options.c in dhcpd in OpenBSD… CVSS 2.0HIGH 7.2
  • TI-2001-00539 Buffer overflow in BSD-based telnetd telnet daemon on various operating systems allows… CVSS 2.0HIGH 10.0
  • TI-2026-40218 sppp_pap_input in sys/net/if_spppsubr.c in OpenBSD before 076e2b1 allows authentication… CVSS 3.1HIGH 8.3
  • TI-2004-00444 Heap-based buffer overflow in proxy_util.c for mod_proxy in Apache 1.3.25 to 1.3.31… CVSS 2.0HIGH 10.0
See all 200 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences