Plonky3: The sponge construction used to get a hash function from a cryptographic permutation is not collision resistant for inputs of different lengths

Exploitation

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

CVSS 4.0

2.9 · CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P · score source

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Vulnerability Currently, when hashing, if the number of elements to hash is not a multiple of the rate, hashiter pads by elements of the current state. This means that it is possible to create iterators of different lengths which lead to an identical hashed state. Given a simple example using a PaddingFreeSponge with width 8 and rate 4. Start with the zero state: [0, 0, 0, 0, 0, 0, 0, 0] Take the first 4 elements to hash and insert into the first 4 elements of the state: [h0, h1, h2, h3, 0, 0, 0, 0] Run the cryptographic permutation on the state: [p00, p10, p20, p30, p40, p50, p60, p70] Take the next 4 elements to hash and insert into the first 4 elements of the state: [h4, h5, h6, h7, p40, p50, p60, p70] Run the cryptographic permutation: [p01, p11, p21, p31, p41, p51, p61, p71] Repeat the above two steps until all elements of the iterator have been consumed. If the number of elements in the iterator is not a multiple of 4 (say there are 10 elements) then, in the final round, the…

Published by the source

16 Apr 2026, 22:52 UTC

Last modified by the source

16 Apr 2026, 22:52 UTC

Source last checked

26 Oct 2026, 15:42 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-3g92-f9ch-qjcm

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# Patch Next advisory brief: GHSA-3g92-f9ch-qjcm

Advisory: Plonky3: The sponge construction used to get a hash function from a cryptographic permutation is not collision resistant for inputs of different lengths
IDs: GHSA-3g92-f9ch-qjcm
Record: https://patchnext.com/advisories/ghsa-3g92-f9ch-qjcm (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: Low (CVSS 2.9)
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 p3-symmetric: affected <= 0.5.2

## Suggested inspection (read-only)
- crates.io p3-symmetric: 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 p3-symmetric.
- 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-3g92-f9ch-qjcm (GitHub-reviewed advisory GHSA-3g92-f9ch-qjcm lists affected ranges: crates.io p3-symmetric >=0 <=0.5.2)

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