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High, CVSS 8.2

libcrux has All-Zero Key Generation Upon Catastrophic RNG Failure

GHSA-434v-x5qv-pmh6

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (libcrux-ed25519 0.0.7), redeploy, then verify what is actually installed.

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

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS 4.0
8.2 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N · score source
EPSS
No dated EPSS signal available.
Source description

As published by the source; long descriptions are shortened.

The libcrux-ed25519 key generation samples Ed25519 secret keys from a provided CSPRNG in a loop for up to 100 attempts until a non-zero key is found. If a non-zero key could not be sampled within 100 attempts the key generation function would silently continue with an all-zero buffer as the secret key. Impact This bug only occurs in the event of a catastrophic failure of the CSPRNG, but would allow anyone to forge signatures under the resulting static signing key. Mitigation Instead of silently continuing with an all-zero signing key, starting from version 0.0.7 key generation will error in the case of 100 failed attempts at sampling a valid key.

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

    Published from ghsa record GHSA-434v-x5qv-pmh6

Agent brief

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# Patch Next advisory brief: GHSA-434v-x5qv-pmh6

Advisory: libcrux has All-Zero Key Generation Upon Catastrophic RNG Failure
IDs: GHSA-434v-x5qv-pmh6
Record: https://patchnext.com/advisories/ghsa-434v-x5qv-pmh6 (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: High (CVSS 8.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: libcrux-ed25519 0.0.7. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io libcrux-ed25519: affected < 0.0.7; fixed in 0.0.7

## Suggested inspection (read-only)
- crates.io libcrux-ed25519: 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 libcrux-ed25519.
- 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-434v-x5qv-pmh6 (GitHub-reviewed advisory GHSA-434v-x5qv-pmh6 lists affected ranges: crates.io libcrux-ed25519 >=0 <0.0.7)

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