CVE-2026-49837GoBGP: BGP OPEN capability parser may read capability values outside declared CapLen boundaries
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 5.9 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
- Weakness (CWE)
- CWE-125
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Deferred
- Record last updated
- Sep 15, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
osrg gobgp osrg:gobgp (from the name) | before 4.6.0 | CNA record |
References
- https://github.com/osrg/gobgp/security/advisories/GHSA-gjrg-jjr3-56cmx-refsource-confirm
- https://github.com/osrg/gobgp/commit/f02ca397821f6ca182ef4eb492c3cbc459552d7cx-refsource-misc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.