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

Advisory record · `GHSA-3g92-f9ch-qjcm`

- **Identifiers:** `GHSA-3g92-f9ch-qjcm`
- **State:** Confirmed
- **Severity:** CVSS 4.0, no score published
- **Critical:** No
- **Weakness (CWE):** [CWE-328](https://cwe.mitre.org/data/definitions/328.html)
- **Tags:** [Weak cryptography or TLS](https://agentprime.io/advisories/tag/weak-crypto.md)
- **Published:** 16 Apr 2026
- **Updated:** 16 Apr 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 16 Apr 2026, 22:52 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `p3-symmetric` (crates.io): affected `<=0.5.2`; no fixed version yet

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> p3-symmetric versions up to and including 0.5.2 are affected. PaddingFreeSponge can produce the same hash for inputs of different lengths when the element count is not a multiple of the rate, so an attacker who controls the number of hashed elements can craft collisions. No fixed version is listed; avoid PaddingFreeSponge where an attacker can control input length.

Written 8 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- Score not published, CVSS 4.0: `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`, from GitHub Advisory Database

- **CISA KEV:** Not listed.
- **EPSS:** No score.

## Timeline

- 31 Oct 2026, 15:18 UTC: First seen by agentprime
- 31 Oct 2026, 15:18 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-3g92-f9ch-qjcm)

## Sources

- [GitHub Advisory Database: GHSA-3g92-f9ch-qjcm](https://github.com/advisories/GHSA-3g92-f9ch-qjcm)
- [OSV: GHSA-3g92-f9ch-qjcm](https://osv.dev/vulnerability/GHSA-3g92-f9ch-qjcm)
- <https://github.com/Plonky3/Plonky3/security/advisories/GHSA-3g92-f9ch-qjcm>
- <https://github.com/Plonky3/Plonky3/commit/5c1dc1d64c0516a8911bbf3ea40f173c21d6ae47>
- <https://github.com/Plonky3/Plonky3>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-3g92-f9ch-qjcm>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-3g92-f9ch-qjcm/>. Everything for agents: <https://agentprime.io/llms.txt>.