CVE-2026-56099 PUBLISHED

OpenBSD mpls_do_error Kernel Stack Memory Disclosure via MPLS Input

Assigner: VulnCheck
Reserved: 18.06.2026 Published: 18.06.2026 Updated: 18.06.2026

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: 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
CVSS Score: 6.9

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	Low	Confidentiality	None
Attack Complexity	Low	Integrity	None	Integrity	None
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CVSS Score: 5.3

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	Low
Privileges Required	None	Integrity Impact	None
User Interaction	None	Availability Impact	None

CVSS 3.1

Product Status

Vendor	openbsd
Product	src
Versions	Default: affected affected from 0 to 6a23123ec05f1eb29cfcaae0f3a468b2e1983cfd (excl.)

CVE-2026-56099 PUBLISHED

OpenBSD mpls_do_error Kernel Stack Memory Disclosure via MPLS Input

Metrics

Product Status

Credits

References

Problem Types