Vulnerability · Published Sep 10, 2026 · Assigned by GitHub_M
CVE-2026-49838GoBGP confederation validation panics on empty AS_PATH attribute
Medium 5.9
In plain English
A medium-severity security flaw in gobgp from osrg. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 36% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
GoBGP is an open source Border Gateway Protocol (BGP) implementation in the Go Programming Language. Prior to version 4.7.0, GoBGP accepts a zero-length AS_PATH during UPDATE decoding and later panics while validating that attribute for a confederation eBGP peer. The vulnerable path is in the BGP UPDATE validator: a malformed UPDATE that should be rejected as a malformed AS_PATH instead reaches an unchecked `p.Value[0]` access, allowing a configured confederation eBGP peer to trigger a denial of service. Version 4.7.0 patches the issue.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | gobgp | no fix listed | DEBIAN-CVE-2026-49838 |
| Debian:13 | gobgp | no fix listed | DEBIAN-CVE-2026-49838 |
| Debian:14 | gobgp | 4.7.0-1 | DEBIAN-CVE-2026-49838 |
| Go | github.com/osrg/gobgp/v4 | 4.7.0 | GO-2026-5954 |
| Go | github.com/osrg/gobgp/v4 | 4.7.0 | GHSA-frrj-87jh-2772 |
| Ubuntu:25.10 | gobgp | no fix listed | UBUNTU-CVE-2026-49838 |
| Ubuntu:26.10 | gobgp | no fix listed | UBUNTU-CVE-2026-49838 |
Affected products (as reported)
Weakness: CWE-129 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- https://github.com/osrg/gobgp/security/advisories/GHSA-frrj-87jh-2772 x_refsource_CONFIRM
- https://github.com/osrg/gobgp/commit/4a319a6c25630fb3cdbda3e9ccfe56e702bdaaa0 x_refsource_MISC