ZcashFoundation Zebra up to 4.4.x Mempool downloads.rs improper synchronization

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.2$0-$5k1.20

Summaryinfo

A vulnerability, which was classified as problematic, was found in ZcashFoundation Zebra up to 4.4.x. Impacted is an unknown function of the file zebrad/src/components/mempool/downloads.rs of the component Mempool. Such manipulation leads to improper synchronization. This vulnerability is documented as CVE-2026-52732. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in ZcashFoundation Zebra up to 4.4.x and classified as problematic. Affected by this issue is some unknown functionality of the file zebrad/src/components/mempool/downloads.rs of the component Mempool. The manipulation with an unknown input leads to a improper synchronization vulnerability. Using CWE to declare the problem leads to CWE-662. The product utilizes multiple threads or processes to allow temporary access to a shared resource that can only be exclusive to one process at a time, but it does not properly synchronize these actions, which might cause simultaneous accesses of this resource by multiple threads or processes. Impacted is availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-52732 since 06/08/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit.

Upgrading to version 4.5.0 eliminates this vulnerability.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.2

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 5.3
CNA Vector (GitHub_M): 🔒

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Improper synchronization
CWE: CWE-662
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Zebra 4.5.0

Timelineinfo

06/08/2026 CVE reserved
08/18/2026 +71 days Advisory disclosed
08/18/2026 +0 days VulDB entry created
08/18/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-52732 (🔒)
GCVE (CVE): GCVE-0-2026-52732
GCVE (VulDB): GCVE-100-391946

Entryinfo

Created: 08/18/2026 21:48
Changes: 08/18/2026 21:48 (65)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Do you want to use VulDB in your project?

Use the official API to access entries easily!