{"schemaVersion":3,"id":"CVE-2026-49837","aliases":["UBUNTU-CVE-2026-49837","DEBIAN-CVE-2026-49837","GHSA-gjrg-jjr3-56cm","GO-2026-5955"],"status":"published","duplicateOf":null,"title":null,"description":"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. 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