CVE-2026-5123: A weakness has been identified in osrg GoBGP up to 4.3.0

Q: How do I fix CVE-2026-5123?

gobgp: upgrade to 4.4.0. Exact commands for each OS are on this page.

Q: Is CVE-2026-5123 being exploited?

CVE-2026-5123 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-5123 affect?

CVE-2026-5123 affects gobgp. Severity is low (CVSS 3.7). 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 remot

Q: How urgent is CVE-2026-5123?

Priority 27/100. Remotely exploitable, no login, no user action

Routine

LOW 3.7REMOTEUPGRADE

CVE-2026-5123 is a low-severity flaw (CVSS 3.7) affecting gobgp. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	3.7 (Low)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 63%)
CISA exploited list	No
Weakness	CWE-189, CWE-193
Published	2026-03-30
Last modified	2026-06-17

Publisher (CNA): VulDB · Vendor: osrg

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-30 16:16 UTCPublished CVE record published
2026-06-17 10:58 UTCUpdated Record last modified

osrg gobgp UPGRADE

Affected: < 4.4.0

Fixed in: 4.4.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy gobgp || rpm -q gobgp || gobgp --version

2. UPGRADE to 4.4.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade gobgp

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade gobgp

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-5123?

gobgp: upgrade to 4.4.0. Exact commands for each OS are on this page.

Is CVE-2026-5123 being exploited?

CVE-2026-5123 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-5123 affect?

CVE-2026-5123 affects gobgp. Severity is low (CVSS 3.7). 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 remot

How urgent is CVE-2026-5123?

Priority 27/100. Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-41642 HIGH 7.5 DOWNGRADE GoBGP is an open source Border Gateway Protocol (BGP) implementation in the Go Programming Language
CVE-2026-42285 HIGH 7.5 DOWNGRADE GoBGP is an open source Border Gateway Protocol (BGP) implementation in the Go Programming Language
CVE-2026-41643 HIGH 7.5 UPGRADE GoBGP is an open source Border Gateway Protocol (BGP) implementation in the Go Programming Language
CVE-2026-7736 HIGH 7.3 UPGRADE A vulnerability was determined in osrg GoBGP up to 4.3.0
CVE-2026-7735 HIGH 7.3 UPGRADE A vulnerability was found in osrg GoBGP up to 4.3.0

References

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