miow invalidly assumes the memory layout of std::net::SocketAddr

Exploitation

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

CVSS

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

EPSS

• CVE-2020-35921: 0.40% estimated exploitation activity in the next 30 days; percentile 33.77 (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.

The miow crate has assumed std::net::SocketAddrV4 and std::net::SocketAddrV6 have the same memory layout as the system C representation sockaddr. It has simply casted the pointers to convert the socket addresses to the system representation. The standard library does not say anything about the memory layout, and this will cause invalid memory access if the standard library changes the implementation. No warnings or errors will be emitted once the change happens.

Published by the source

25 Aug 2021, 20:50 UTC

Last modified by the source

13 Jun 2023, 18:42 UTC

Source last checked

26 Oct 2026, 15:34 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-jrcf-4jp8-m28v

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# Patch Next advisory brief: CVE-2020-35921

Advisory: miow invalidly assumes the memory layout of std::net::SocketAddr
IDs: CVE-2020-35921, GHSA-jrcf-4jp8-m28v
Record: https://patchnext.com/advisories/cve-2020-35921 (revision 1, source checked 26 Oct 2026, 15:34 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: miow 0.3.6. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io miow: affected >= 0.3.0, < 0.3.6; fixed in 0.3.6

## Suggested inspection (read-only)
- crates.io miow: 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 miow.
- 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-jrcf-4jp8-m28v (GitHub-reviewed advisory GHSA-jrcf-4jp8-m28v lists affected ranges: crates.io miow >=0.3.0 <0.3.6)

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