CVE-2025-43972 GoBGP crashes in the flowspec parser

What is CVE-2025-43972?

CVE-2025-43972 is a medium-severity denial of service vulnerability in GoBGP, published on 21 Apr 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

An issue was discovered in GoBGP before 3.35.0. An attacker can cause a crash in the pkg/packet/bgp/bgp.go flowspec parser by sending fewer than 20 bytes in a certain context.

Weakness: CWE-1284

Which versions are affected by CVE-2025-43972?

6 open source packages ship an affected version, including github.com/osrg/gobgp and github.com/osrg/gobgp/v3. It affects 1 product.

Products include Osrg Gobgp.

How do I fix CVE-2025-43972?

Upgrade to a fixed version.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2025-43972 being exploited?

There is no known exploitation of CVE-2025-43972 in the wild and no public exploit code.

Other vulnerabilities in GoBGP

• CVE-2025-43971 GoBGP panics due to a zero value for softwareVersionLen High 8.6
• CVE-2026-41642 GoBGP: Remote Denial of Service (Panic) via Malformed Well-known Path Attribute High 7.5
• CVE-2026-41643 GoBGP: Remote Denial of Service (Panic) in UpdatePathAttrs4ByteAs via Malformed BGP UPDATE High 7.5
• CVE-2026-42285 GoBGP: Panic in AdjRib.Update via malformed BGP Update message (Nil Pointer Dereference) High 7.5
• CVE-2026-37461 GoBGP has an out-of-bounds read in the ParseIP6Extended function High 7.5

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2025-43972, GHSA-mfvv-mgf6-q25r, GO-2025-3632, MINI-7698-wf85-26f6, MINI-x7v9-629g-g696, UBUNTU-CVE-2025-43972.