CVE-2026-41643: GoBGP has Remote Denial of Service (Panic) in UpdatePathAttrs4ByteAs via Malformed BGP UPDATE

CVE-2026-41643 · Severity: high · CVSS 7.5 · Published 2026-05-07

GoBGP is an open source Border Gateway Protocol (BGP) implementation in the Go Programming Language. Prior to version 4.3.0, a remote Denial of Service (DoS) vulnerability exists in GoBGP where a malformed BGP UPDATE message can trigger a runtime error: index out of range panic. This occurs during the processing of 4-byte AS attributes when the message structure causes an internal slice index shift that is not properly handled. This issue has been patched in version 4.3.0.

Technologies: github.com/osrg/gobgp/v4 (Go), Osrg Gobgp. Vendors: Go, Osrg.

Quick answers

Is CVE-2026-41643 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-41643 being exploited in the wild.
How severe is CVE-2026-41643?
High severity, with a CVSS score of 7.5, published 7 May 2026.
Which products and versions are affected?
github.com/osrg/gobgp/v4 (Go) SEMVER:introduced=0,fixed=4.3.0.
Is there a fix for CVE-2026-41643?
Yes. github.com/osrg/gobgp/v4 (Go): upgrade to 4.3.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2026-41643?
Check whether you run github.com/osrg/gobgp/v4 (Go) or Osrg Gobgp at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • github.com/osrg/gobgp/v4 (Go): upgrade to 4.3.0 or later
    go get github.com/osrg/gobgp/v4@v4.3.0

Affected products

  • github.com/osrg/gobgp/v4 (Go) SEMVER:introduced=0,fixed=4.3.0
  • Osrg Gobgp

Identifiers

  • CVE-2026-41643
  • GHSA-8rxh-r2p6-7f2q
  • GO-2026-5266

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