CVE-2026-46654 Plonky3 MultiField32Challenger: transcript malleability and challenge entropy loss
An attacker can craft distinct transcripts producing identical challenges, breaking Fiat-Shamir binding in Plonky3 polynomial IOPs.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-46654?
CVE-2026-46654 is a high-severity vulnerability in Plonky3, published on 10 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Plonky3 is a toolkit for polynomial IOPs (PIOPs). Prior to versions 0.4.3 and 0.5.3, an attacker controlling prover-side observations can craft distinct transcripts that produce identical challenges, breaking the binding property of Fiat-Shamir. This issue has been patched in versions 0.4.3 and 0.5.3.
Which versions are affected by CVE-2026-46654?
4 open source packages ship an affected version, including p3-challenger.
| Package | Affected | Fixed in |
|---|---|---|
p3-challenger crates.io | All versions | 0.4.3 |
p3-challenger crates.io | All versions | 0.4.3 |
p3-challenger crates.io | From 0.5.0 | 0.5.3 |
p3-challenger crates.io | From 0.5.0 | 0.5.3 |
How do I fix CVE-2026-46654?
Upgrade p3-challenger to a fixed version for your release line: 0.4.3 or 0.5.3.
Is CVE-2026-46654 being exploited?
There is no known exploitation of CVE-2026-46654 in the wild and no public exploit code.
Sources
Also known as GHSA-vj64-rjf3-w3v7.