Zebra before 6.2.1 Block Download Denial of Service via KnownBlock SentHashes Lockout
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.
CVE-2026-104421
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-104421
zebra
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"vendor": "ZcashFoundation",
"product": "zebra",
"versions": [
{
"status": "affected",
"version": "0",
"lessThan": "6.2.1",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.2.1",
"versionType": "semver"
}
],
"packageURL": "pkg:cargo/zebrad",
"defaultStatus": "unaffected"
}
]- Related CVEs
- CVE-2026-104421
Source reference:
/cveMetadata/cveId
Publisher severity
medium
Source reference: /containers/cna/metrics
- Event
- #7904 · Revision 1
- Added to Heist Feed
- Publisher date