{"id":"UBUNTU-CVE-2026-49837","details":"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.","modified":"2026-09-16T14:01:38.295943847Z","published":"2026-09-10T22:16:00Z","upstream":["CVE-2026-49837"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-49837"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-49837"},{"type":"REPORT","url":"https://github.com/osrg/gobgp/security/advisories/GHSA-gjrg-jjr3-56cm"}],"affected":[{"package":{"name":"gobgp","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/gobgp?arch=source&distro=esm-apps%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.15-1","1.29-1","1.29-1ubuntu0.1+esm1","1.29-1ubuntu0.1+esm2"],"ecosystem_specific":{"binaries":[{"binary_name":"gobgpd","binary_version":"1.29-1ubuntu0.1+esm2"},{"binary_name":"golang-github-osrg-gobgp-dev","binary_version":"1.29-1ubuntu0.1+esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49837.json"}},{"package":{"name":"gobgp","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/gobgp?arch=source&distro=esm-apps%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.33-1","2.11.0-1","2.12.0-1","2.12.0-1ubuntu0.1~esm1","2.12.0-1ubuntu0.1~esm2","2.12.0-1ubuntu0.1~esm3"],"ecosystem_specific":{"binaries":[{"binary_version":"2.12.0-1ubuntu0.1~esm3","binary_name":"gobgpd"},{"binary_name":"golang-github-osrg-gobgp-dev","binary_version":"2.12.0-1ubuntu0.1~esm3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49837.json"}},{"package":{"name":"gobgp","ecosystem":"Ubuntu:Pro:22.04:LTS","purl":"pkg:deb/ubuntu/gobgp?arch=source&distro=esm-apps%2Fjammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.25.0-2","2.25.0-3","2.25.0-3build1","2.25.0-3ubuntu0.1","2.25.0-3ubuntu0.1+esm1","2.25.0-3ubuntu0.1+esm2","2.25.0-3ubuntu0.1+esm3","2.25.0-3ubuntu0.1+esm4"],"ecosystem_specific":{"binaries":[{"binary_name":"gobgpd","binary_version":"2.25.0-3ubuntu0.1+esm4"},{"binary_name":"golang-github-osrg-gobgp-dev","binary_version":"2.25.0-3ubuntu0.1+esm4"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49837.json"}},{"package":{"name":"gobgp","ecosystem":"Ubuntu:Pro:24.04:LTS","purl":"pkg:deb/ubuntu/gobgp?arch=source&distro=esm-apps%2Fnoble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.16.0-1build1","3.19.0-1","3.21.0-1","3.23.0-1","3.23.0-1ubuntu0.1","3.23.0-1ubuntu0.2","3.23.0-1ubuntu0.2+esm1","3.23.0-1ubuntu0.3","3.23.0-1ubuntu0.3+esm1","3.23.0-1ubuntu0.3+esm2","3.23.0-1ubuntu0.3+esm3","3.23.0-1ubuntu0.3+esm4"],"ecosystem_specific":{"binaries":[{"binary_version":"3.23.0-1ubuntu0.3+esm4","binary_name":"gobgpd"},{"binary_version":"3.23.0-1ubuntu0.3+esm4","binary_name":"golang-github-osrg-gobgp-dev"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49837.json"}},{"package":{"name":"gobgp","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/gobgp?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.35.0-1","3.36.0-2"],"ecosystem_specific":{"binaries":[{"binary_name":"gobgpd","binary_version":"3.36.0-2"},{"binary_name":"golang-github-osrg-gobgp-dev","binary_version":"3.36.0-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49837.json"}},{"package":{"name":"gobgp","ecosystem":"Ubuntu:Pro:26.04:LTS","purl":"pkg:deb/ubuntu/gobgp?arch=source&distro=esm-apps%2Fresolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.36.0-2","3.36.0-2build1","3.36.0-2ubuntu0.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_version":"3.36.0-2ubuntu0.1~esm1","binary_name":"gobgpd"},{"binary_name":"golang-github-osrg-gobgp-dev","binary_version":"3.36.0-2ubuntu0.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49837.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N"},{"type":"Ubuntu","score":"medium"}]}