CVE-2026-52732
An attacker can advertise fake transaction identifiers and remain silent so each task holds a slot until TRANSACTION_DOWNLOAD_TIMEOUT, then periodically refill the queue as slots expire.
Does this matter?
Lower severity and a low EPSS score (0.37%). Track it; it rarely justifies an emergency change on its own.
Description
ZEBRA is a Zcash node written entirely in Rust. Prior to 4.5.0, one unauthenticated P2P peer can monopolize all 25 MAX_INBOUND_CONCURRENCY slots in Zebra's inbound mempool download and verification pipeline. In zebrad/src/components/mempool/downloads.rs, the bounded queue was shared globally without per-peer accounting, while peer identity was not carried through Gossip and FullQueue responses were mapped to Response::Nil instead of reaching overload disconnection handling. An attacker can advertise fake transaction identifiers and remain silent so each task holds a slot until TRANSACTION_DOWNLOAD_TIMEOUT, then periodically refill the queue as slots expire. While saturated, honest peer transactions and local sendrawtransaction requests are rejected with MempoolError::FullQueue, although block validation and synchronization continue. This issue is fixed in version 4.5.0.
- CVSS 3.1
- 5.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- EPSS
- 0.37% probability · 31th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-770
- Source
- security-advisories@github.com
References
- https://github.com/ZcashFoundation/zebra/commit/1440b43ca7df59aca948090d45117557b217a6cd
- https://github.com/ZcashFoundation/zebra/releases/tag/v4.5.0
- https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-4fc2-h7jh-287c
- https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-4fc2-h7jh-287c
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.