zebrad has unbounded memory leak in mempool download pipeline via timeout path cancel_handles retention

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS

• CVE-2026-52734: 0.51% estimated exploitation activity in the next 30 days; percentile 43.30 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Am I affected You are affected if: 1. You run zebrad up to and including v4.4.1. 2. Your node accepts inbound P2P connections (network.listenaddr is set, which is the default). 3. Your node's mempool is active (node is synced near the chain tip). All default configurations are affected. Summary The mempool download pipeline's cancelhandles map retains entries for transactions whose verification times out at the outer RATELIMITDELAY (73-second) boundary. The tokio::time::error::Elapsed error carries no payload, so the transaction ID is unrecoverable and the corresponding cancelhandles entry (including the full Gossip::Tx(UnminedTx), up to ~2 MB) is never removed. Entries accumulate monotonically with no upper bound or garbage collection, leading to eventual out-of-memory process termination. Details Downloads::pollnext() at zebrad/src/components/mempool/downloads.rs:215-228 handles three terminal states for a verification task: - Ok(Ok(...)): success. Calls…

Published by the source

2 Jul 2026, 20:12 UTC

Last modified by the source

2 Jul 2026, 20:12 UTC

Source last checked

26 Oct 2026, 15:42 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-65jj-fmw8-468q

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# Patch Next advisory brief: CVE-2026-52734

Advisory: zebrad has unbounded memory leak in mempool download pipeline via timeout path cancel_handles retention
IDs: CVE-2026-52734, GHSA-65jj-fmw8-468q
Record: https://patchnext.com/advisories/cve-2026-52734 (revision 1, source checked 26 Oct 2026, 15:42 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: zebrad 4.5.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io zebrad: affected <= 4.4.1; fixed in 4.5.0

## Suggested inspection (read-only)
- crates.io zebrad: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on zebrad.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-65jj-fmw8-468q (GitHub-reviewed advisory GHSA-65jj-fmw8-468q lists affected ranges: crates.io zebrad >=0 <=4.4.1)

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