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CVE-2026-49837GHSA-GJRG-JJR3-56CMGO-2026-5955

GoBGP: BGP OPEN capability parser may read capability values outside declared CapLen boundaries

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 4.6.0
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

GoBGP is an open source Border Gateway Protocol (BGP) implementation in the Go Programming Language. Versions prior to 4.6.0 contain a BGP OPEN capability parsing issue where several concrete capability decoders may parse data from the full remaining capability buffer instead of the slice bounded by the declared capability length, `CapLen`. A malformed BGP OPEN message can cause bytes from a following capability to be interpreted as part of the current capability. The most security-relevant case is the 4-octet AS capability, where a capability with `CapLen == 0` may cause the parser to read bytes from the following capability as the 4-octet AS value. This parsed value may later affect peer AS validation during BGP session establishment. Version 4.6.0 patches the issue.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • osrg gobgp

    fixed in 4.6.0

  • github.com/osrg/gobgp/v4Go

    fixed in 4.6.0

References 2

GitHub · osrg/gobgp