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

Source: https://junglewise.ai/threats/cve-2026-41643-gobgp-has-remote-denial-of-service-panic-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-07  
License: CC BY 4.0 with a link back

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)](https://junglewise.ai/threats/technologies/github-com-osrg-gobgp-v4), [Osrg Gobgp](https://junglewise.ai/threats/technologies/gobgp). Vendors: [Go](https://junglewise.ai/threats/vendors/go), [Osrg](https://junglewise.ai/threats/vendors/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

  ```sh
  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

## Related threats

- [osrg GoBGP denial of service via empty AS_PATH attribute](https://junglewise.ai/threats/cve-2026-49838-osrg-gobgp-denial-of-service-via-empty-as-path-attribute)
- [GoBGP out-of-bounds read in BGP OPEN capability parser](https://junglewise.ai/threats/cve-2026-49837-gobgp-out-of-bounds-read-in-bgp-open-capability-parser)
- [GoBGP integer underflow in BGPUpdate.DecodeFromBytes](https://junglewise.ai/threats/cve-2026-37462-gobgp-integer-underflow-in-bgpupdate-decodefrombytes)
- [osrg GoBGP nil pointer dereference in AdjRib.Update](https://junglewise.ai/threats/cve-2026-42285-osrg-gobgp-nil-pointer-dereference-in-adjrib-update)
- [GO-2026-5198 - GoBGP: Remote Denial of Service (Panic) via Malformed Well-known Path Attribute in github.com/osrg/gobgp](https://junglewise.ai/threats/cve-2026-41642-gobgp-has-remote-denial-of-service-panic-via-malformed-well-known)