CVE-2026-52734
ZEBRA: Unbounded memory leak in mempool download pipeline via timeout path cancel_handles retention
Description
ZEBRA is a Zcash node written entirely in Rust. Prior to 4.5.0, an unauthenticated P2P peer can cause the mempool download pipeline to retain transactions after verification reaches the outer RATE_LIMIT_DELAY timeout. In zebrad/src/components/mempool/downloads.rs, Downloads::poll_next removed cancel_handles entries after success and ordinary verification errors, but tokio::time::error::Elapsed did not carry the UnminedTxId needed to remove the timed-out entry. Each retained cancel_handles entry could hold a full Gossip::Tx(UnminedTx), while normal mined-transaction cleanup could not match attacker transactions and no periodic garbage collection or count cap existed. Sustained traffic therefore caused monotonic memory growth until swap pressure degraded the node or the operating system terminated the zebrad process for exhausting memory. This issue is fixed in version 4.5.0.
INFO
Published Date :
Aug. 18, 2026, 8:17 p.m.
Last Modified :
Aug. 19, 2026, 7:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE |
Solution
- Update Zcash node to version 4.5.0 or later.
- Apply vendor patches for mempool download handling.
- Monitor memory usage after the update.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-52734.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-52734 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-52734
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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The following list is the news that have been mention
CVE-2026-52734 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-52734 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Aug. 19, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-52734', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-08-19T18:17:27.998662Z'} -
New CVE Received by [email protected]
Aug. 18, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'ZcashFoundation', 'product': 'zebra', 'versions': [{'status': 'affected', 'version': '< 4.5.0'}]}] Added Description ZEBRA is a Zcash node written entirely in Rust. Prior to 4.5.0, an unauthenticated P2P peer can cause the mempool download pipeline to retain transactions after verification reaches the outer RATE_LIMIT_DELAY timeout. In zebrad/src/components/mempool/downloads.rs, Downloads::poll_next removed cancel_handles entries after success and ordinary verification errors, but tokio::time::error::Elapsed did not carry the UnminedTxId needed to remove the timed-out entry. Each retained cancel_handles entry could hold a full Gossip::Tx(UnminedTx), while normal mined-transaction cleanup could not match attacker transactions and no periodic garbage collection or count cap existed. Sustained traffic therefore caused monotonic memory growth until swap pressure degraded the node or the operating system terminated the zebrad process for exhausting memory. This issue is fixed in version 4.5.0. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Added CWE CWE-401 Added Reference https://github.com/ZcashFoundation/zebra/commit/1440b43ca7df59aca948090d45117557b217a6cd Added Reference https://github.com/ZcashFoundation/zebra/releases/tag/v4.5.0 Added Reference https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-65jj-fmw8-468q