Vulnerability · Published Mar 30, 2026 · Assigned by VulDB

CVE-2026-5123osrg GoBGP bgp.go DecodeFromBytes off-by-one

Low 3.7

In plain English

A low-severity security flaw in GoBGP from osrg. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)3.7Low

Exploit odds (30 days)0.4%top 63.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

A weakness has been identified in osrg GoBGP up to 4.3.0. This impacts the function DecodeFromBytes of the file pkg/packet/bgp/bgp.go. Executing a manipulation of the argument data[1] can lead to off-by-one. The attack may be launched remotely. Attacks of this nature are highly complex. The exploitability is said to be difficult. This patch is called 67c059413470df64bc20801c46f64058e88f800f. A patch should be applied to remediate this issue.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	gobgp	no fix listed	DEBIAN-CVE-2026-5123
Debian:13	gobgp	no fix listed	DEBIAN-CVE-2026-5123
Debian:14	gobgp	4.4.0-1	DEBIAN-CVE-2026-5123
Ubuntu:25.10	gobgp	no fix listed	UBUNTU-CVE-2026-5123
Ubuntu:26.10	gobgp	no fix listed	UBUNTU-CVE-2026-5123

Affected products (as reported)

Vendor	Product	Versions
osrg	GoBGP	4.04.14.24.3.0

Weakness: CWE-193, CWE-189 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L/E:X/RL:O/RC:C

References

VDB-354155 | osrg GoBGP bgp.go DecodeFromBytes off-by-one vdb-entry, technical-description
VDB-354155 | CTI Indicators (IOB, IOC, IOA) signature, permissions-required
Submit #780179 | osrg GoBGP 4.3.0 Off-by-one Error third-party-advisory
https://github.com/osrg/gobgp/pull/3342 issue-tracking, patch
https://github.com/osrg/gobgp/commit/67c059413470df64bc20801c46f64058e88f800f patch
https://github.com/osrg/gobgp/ product