CVE-2026-7736: GoBGP Integer Underflow Vulnerability

github.com/osrg/gobgp/v4 Updated 08 May 2026

Summary

04/05/2026

Disclosed on

CVE-2026-7736

CVE

Yes i

Fix available

Moderate

Severity

7.3

CVSS Score

CVE-2026-7736: GoBGP has an Integer Underflow Issue. Affects github.com/osrg/gobgp/v4 versions < 4.4.0. Fixed in 4.4.0. How to fix ↓

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Background

GoBGP is an open-source Border Gateway Protocol (BGP) implementation written in Go, designed to facilitate the exchange of routing information between different networks. It is widely used for its performance and flexibility in managing BGP sessions. However, versions up to 4.3.0 are susceptible to an integer underflow issue that can be exploited remotely, potentially compromising the integrity of the routing information.

Vulnerability Detail

The vulnerability arises from an integer underflow in the parseRibEntry function located in pkg/packet/mrt/mrt.go. This flaw allows an attacker to manipulate input data, leading to unexpected behavior and potential exploitation. The ramifications include the possibility of remote code execution or denial of service, making it critical for users to address this issue promptly.

How To Fix

Latest published version: v4.10.0 as of 22 Oct 2026

go get github.com/osrg/gobgp/v4@v4.10.0

Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.

If you need the minimum change

4.4.0

This is the first release that contains the fix.

go get github.com/osrg/gobgp/v4@v4.4.0

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Workaround

Currently, there are no specific workarounds recommended for this vulnerability. The best course of action is to upgrade to the patched version as soon as possible.

Conclusion

The integer underflow vulnerability in GoBGP (CVE-2026-7736) poses a significant risk to users of versions up to 4.3.0. It is crucial to upgrade to version 4.4.0 to mitigate this risk. Users are encouraged to utilize tools like Vulert to monitor for vulnerabilities in their applications.

See every vulnerability recorded for github.com/osrg/gobgp/v4 →