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High, CVSS 8.1

Data races in lexer

CVE-2020-36458GHSA-f997-8gxg-r354

What to do

Vendor response not established. Follow the primary source's mitigation guidance and check back for a fix.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

  • crates.io lexer

    Affected
    <= 0.1.16
    Fixed in
    no fixed version recorded

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
8.1 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
  • CVE-2020-36458: 0.83% estimated exploitation activity in the next 30 days; percentile 57.68 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

lexer is a plugin based lexical reader.Affected versions of this crate implements Sync for ReaderResult<T, E with the trait bound T: Send, E: Send. Since matching on the public enum ReaderResult<T, E provides access to &T & &E, allowing data race to a non-Sync type T or E. This can result in a memory corruption when multiple threads concurrently access &T or &E. Suggested fix for the bug is change the trait bounds imposed on T & E to be T: Sync, E: Sync.

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 1 · created ·

    Published from ghsa record GHSA-f997-8gxg-r354

Agent brief

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2020-36458

Advisory: Data races in lexer
IDs: CVE-2020-36458, GHSA-f997-8gxg-r354
Record: https://patchnext.com/advisories/cve-2020-36458 (revision 1, source checked 26 Oct 2026, 15:33 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io lexer: affected <= 0.1.16

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

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on lexer.
- 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-f997-8gxg-r354 (GitHub-reviewed advisory GHSA-f997-8gxg-r354 lists affected ranges: crates.io lexer >=0 <=0.1.16)

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