Skip to content
Patch Next
Sign inAdd to your agent

← Actionable
High, CVSS 7.4

pqc_kyber KyberSlash: division timings depending on secrets

GHSA-x5j2-g63m-f8g4

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.

Add to your agent

Affected packages

  • crates.io pqc_kyber

    Affected
    <= 0.7.1
    Fixed in
    no fixed version recorded

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
7.4 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS
No dated EPSS signal available.
Source description

As published by the source; long descriptions are shortened.

Various Kyber software libraries in various environments leak secret information into timing, specifically because these libraries include a line of code that divides a secret numerator by a public denominator, the number of CPU cycles for division in various environments varies depending on the inputs to the division, and this variation appears within the range of numerators used in these libraries. The KyberSlash pages track which Kyber libraries have this issue, and include a FAQ about the issue. Author The KyberSlash pages were written by Daniel J. Bernstein. The FAQ originally said "I", but some people seemed to have trouble finding this authorship statement, so the FAQ now says "Bernstein" instead. URL The permanent link for the KyberSlash pages is https://kyberslash.cr.yp.to. Mitigation status in pqckyber crate The issues has not been resolved in the pqckyber crate. A third-party fork that mitigates this attack vector has been published as safepqckyber.

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

    Published from ghsa record GHSA-x5j2-g63m-f8g4

Agent brief

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

# Patch Next advisory brief: GHSA-x5j2-g63m-f8g4

Advisory: pqc_kyber KyberSlash: division timings depending on secrets
IDs: GHSA-x5j2-g63m-f8g4
Record: https://patchnext.com/advisories/ghsa-x5j2-g63m-f8g4 (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: High (CVSS 7.4)
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 pqc_kyber: affected <= 0.7.1

## Suggested inspection (read-only)
- crates.io pqc_kyber: 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 pqc_kyber.
- 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-x5j2-g63m-f8g4 (GitHub-reviewed advisory GHSA-x5j2-g63m-f8g4 lists affected ranges: crates.io pqc_kyber >=0 <=0.7.1)

Commands are suggestions: review each one before running it.

Loading voting…