{"id":"CVE-2026-49837","title":"GoBGP is an open source Border Gateway Protocol (BGP) implementation in the Go Programming Language","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 f…","severity":"medium","cvss":5.9,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","cwe":["CWE-125"],"vendor":"osrg","product":"gobgp","affected":["gobgp < 4.6.0"],"patched":["github.com/osrg/gobgp/v4 4.6.0"],"published":"2026-09-10","updated":"2026-09-16","sourceUpdated":"2026-09-16T13:42:46.953","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-49837","references":[{"url":"https://github.com/osrg/gobgp/commit/f02ca397821f6ca182ef4eb492c3cbc459552d7c","label":"security-advisories@github.com"},{"url":"https://github.com/osrg/gobgp/security/advisories/GHSA-gjrg-jjr3-56cm","label":"security-advisories@github.com"},{"url":"https://github.com/advisories/GHSA-gjrg-jjr3-56cm"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-49837.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-49837"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2531682"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-49837"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-49837"}],"tags":["nvd","cve.org","ghsa","go","csaf","vex","red-hat"],"epss":0.00255,"epssPercentile":0.17429,"aliases":["GHSA-gjrg-jjr3-56cm"],"ecosystem":"go","ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-09-15T15:10:05.962553Z"},"ingestedAt":"2026-07-09T23:53:27.211Z","scores":{"nvd":5.9,"vendor":7.4},"slug":"CVE-2026-49837","body":"## Overview\n\nGoBGP 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-49837)\n\nAffected packages:\n\n- `github.com/osrg/gobgp/v4 <= 4.5.0`\n\nPatched in:\n\n- `github.com/osrg/gobgp/v4 4.6.0`\n\nSource: https://github.com/advisories/GHSA-gjrg-jjr3-56cm\n\n## Vendor advisories\n\n- **Red Hat VEX** · Important · affected: Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat OpenShift Container Platform 4 · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-49837.json)","depth":"sunlit","depthScore":33,"depthScoreParts":{"impact":32.5,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}