rustix's rustix::fs::Dir iterator with the linux_raw backend can cause memory explosion

Exploitation

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

CVSS

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

EPSS

• CVE-2024-43806: 0.48% estimated exploitation activity in the next 30 days; percentile 41.48 (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.

Summary When using rustix::fs::Dir using the linuxraw backend, it's possible for the iterator to "get stuck" when an IO error is encountered. Combined with a memory over-allocation issue in rustix::fs::Dir::readmore, this can cause quick and unbounded memory explosion (gigabytes in a few seconds if used on a hot path) and eventually lead to an OOM crash of the application. Details Discovery The symptoms were initially discovered in https://github.com/imsnif/bandwhich/issues/284. That post has lots of details of our investigation. See this post and the Discord thread for details. Diagnosis This issue is caused by the combination of two independent bugs: 1. Stuck iterator - The rustix::fs::Dir iterator can fail to halt after encountering an IO error, causing the caller to be stuck in an infinite loop. 2. Memory over-allocation - Dir::readmore incorrectly grows the read buffer unconditionally each time it is called, regardless of necessity. Since <Dir as Iterator::next calls Dir::read,…

Published by the source

18 Oct 2023, 18:27 UTC

Last modified by the source

27 Aug 2024, 14:22 UTC

Source last checked

26 Oct 2026, 15:38 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-c827-hfw6-qwvm

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# Patch Next advisory brief: CVE-2024-43806

Advisory: rustix's `rustix::fs::Dir` iterator with the `linux_raw` backend can cause memory explosion
IDs: CVE-2024-43806, GHSA-c827-hfw6-qwvm
Record: https://patchnext.com/advisories/cve-2024-43806 (revision 1, source checked 26 Oct 2026, 15:38 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: rustix 0.38.19, 0.37.25, 0.36.16, 0.35.15. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io rustix: affected >= 0.35.11, < 0.35.15; >= 0.36.0, < 0.36.16; >= 0.37.0, < 0.37.25; >= 0.38.0, < 0.38.19; fixed in 0.35.15, 0.36.16, 0.37.25, 0.38.19

## Suggested inspection (read-only)
- crates.io rustix: 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 rustix.
- 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-c827-hfw6-qwvm (GitHub-reviewed advisory GHSA-c827-hfw6-qwvm lists affected ranges: crates.io rustix >=0.35.11 =0.36.0 =0.37.0 =0.38.0 <0.38.19)

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