CVE-2026-49838
MediumCVSS 5.9Exploitation Probability (EPSS)
Low risk27th percentile - higher than 27% of all known CVEs
Summary
GoBGP, a BGP implementation in Go, prior to version 4.7.0 accepts a zero-length AS_PATH during UPDATE decoding and later panics while validating that attribute for a confederation eBGP peer. A malformed UPDATE that should be rejected as an invalid AS_PATH 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.
Risk Assessment
A malicious or misconfigured confederation eBGP peer can trigger a panic and crash the GoBGP process, causing a BGP routing disruption.
Recommendation
Update GoBGP to version 4.7.0 or later. Limit trust to confederation eBGP peers to the necessary minimum.
Other vulnerabilities in GoBGP
See all- CVE-2026-42285High
In version 4.4.0 of GoBGP, an unauthenticated remote BGP peer can trigger a fatal panic by sending a specially crafted BGP UPDATE message. This bug causes the entire GoBGP process to crash, resulting in a complete loss of service availability.
- CVE-2026-41643High
GoBGP, an open source implementation of the BGP protocol in Go, prior to version 4.3.0 has a remote Denial of Service (DoS) vulnerability. A malformed BGP UPDATE message can trigger a runtime error related to an index out of range.
- CVE-2026-41642High
In version 4.3.0 of GoBGP, an open source BGP implementation, a remote Denial of Service (DoS) vulnerability exists due to a nil pointer dereference. A malformed BGP UPDATE message containing an unrecognized Path Attribute marked as 'Well-known' leads to a process crash.
- CVE-2026-37461High
An out-of-bounds read in the ParseIP6Extended function in gobgp v4.3.0 allows attackers to cause a Denial of Service (DoS) by supplying a crafted BGP UPDATE message.
- CVE-2026-49837Medium
GoBGP, a BGP implementation in Go, prior to version 4.6.0 has a BGP OPEN capability parsing issue where several capability decoders may read from the full remaining capability buffer instead of the slice bounded by the declared CapLen. A malformed BGP OPEN message can cause bytes from a following capability to be interpreted as part of the current one; the most security-relevant case is the 4-octet AS capability, where 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.
- CVE-2026-37462High
An integer underflow in the BGPUpdate.DecodeFromBytes function (/bgp/bgp.go) of gobgp v4.3.0 allows attackers to cause a denial of service by sending a crafted BGP UPDATE message.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS