cggmp24 and cggmp21 are vulnerable to signature forgery through altered presignatures

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

• CVE-2025-66017: 0.22% estimated exploitation activity in the next 30 days; percentile 13.06 (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.

Impact This attack is against presignatures used in very specific context: Presignatures + HD wallets derivation: security level reduces to 85 bits \ Previously users could generate a presignature, and then choose a HD derivation path while issuing a partial signature via Presignature::setderivationpath, which is malleable to attack that reduces target security level. To mitigate, this method has been removed from API. Presignatures + "raw signing" (when signer signs a hash without knowing an original message): results into signature forgery attack \ Previously, users were able to configure Presignature::issuepartialsignature with hashed message without ever providing original mesage. In new API, this method only accepts digests for which original message has been observed. Patches cggmp24 v0.7.0-alpha.2 release contains API changes that make it impossible to use presignatures in contexts in which it reduces security. Follow migration guidelines to upgrade. Workarounds Users can…

Published by the source

25 Nov 2025, 20:42 UTC

Last modified by the source

27 Nov 2025, 09:00 UTC

Source last checked

26 Oct 2026, 15:39 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-8frv-q972-9rq5

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# Patch Next advisory brief: CVE-2025-66017

Advisory: cggmp24 and cggmp21 are vulnerable to signature forgery through altered presignatures
IDs: CVE-2025-66017, GHSA-8frv-q972-9rq5
Record: https://patchnext.com/advisories/cve-2025-66017 (revision 1, source checked 26 Oct 2026, 15:39 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: Partial vendor fix; fixed versions by package: cggmp24 0.7.0-alpha.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io cggmp24: affected < 0.7.0-alpha.2; fixed in 0.7.0-alpha.2
- crates.io cggmp21: affected <= 0.6.3

## Suggested inspection (read-only)
- crates.io cggmp24: check the installed version with your package manager.
- crates.io cggmp21: 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 cggmp24, cggmp21.
- 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-8frv-q972-9rq5 (GitHub-reviewed advisory GHSA-8frv-q972-9rq5 lists affected ranges: crates.io cggmp21 >=0 =0 <0.7.0-alpha.2)

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