CVE-2026-49837 (GCVE-0-2026-49837)

Vulnerability from cvelistv5 – Published: 2026-09-10 21:56 – Updated: 2026-09-15 15:10
VLAI
Title
GoBGP: BGP OPEN capability parser may read capability values outside declared CapLen boundaries
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.
Severity
5.9 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-15 15:10 UTC
CWE
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7632 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
osrg gobgp Affected: < 4.6.0
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

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