What is GHSA-xx63-6p6j-3wv7?

GHSA-xx63-6p6j-3wv7 is a security advisory published by GitHub Security Advisories with Medium severity. Zebra before 6.2.1 contains an incomplete cleanup vulnerability that allows unauthenticated peers...

Which CVE IDs does GHSA-xx63-6p6j-3wv7 cover?

GHSA-xx63-6p6j-3wv7 covers the following CVE IDs: CVE-2026-104421. Each CVE has its own detail page on EchelonGraph Pulse with the synthesized EG score.

What is the CVSS v3 score of GHSA-xx63-6p6j-3wv7?

GHSA-xx63-6p6j-3wv7 has a CVSS v3 base score of 5.3, published by GitHub Security Advisories.

GHSA-xx63-6p6j-3wv7MediumCVSS 5.3

Zebra before 6.2.1 contains an incomplete cleanup vulnerability that allows unauthenticated peers...

Vendor

GitHub Security Advisories

Published

October 2, 2026

Last Modified

October 2, 2026

🔗 CVE IDs covered (1)

CVE-2026-104421 →

📋 Description

Zebra before 6.2.1 contains an incomplete cleanup vulnerability that allows unauthenticated peers to block downloading of valid blocks by leaving rejected hashes in SentHashes. Attackers can send a contextually invalid block sharing an honest block's header hash, causing Request::KnownBlock to skip the honest block and keep nodes behind the tip.

🔗 References (4)

https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-x93j-mj2f-q338
https://nvd.nist.gov/vuln/detail/CVE-2026-104421
https://www.vulncheck.com/advisories/zebra-before-6.2.1-block-download-denial-of-service-via-knownblock-senthashes-lockout
https://github.com/advisories/GHSA-xx63-6p6j-3wv7