GHSA-vj64-rjf3-w3v7
GHSA-vj64-rjf3-w3v7 is a CWE-345 vulnerability in p3-challenger. O3 Security confirms whether GHSA-vj64-rjf3-w3v7 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Plonky3 MultiField32Challenger: transcript malleability and challenge entropy loss
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-vj64-rjf3-w3v7.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
p3-challenger🦀p3-challengerReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
Impact
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Key:
challenger/src/multi_field_challenger.rs|MultiField32Challenger::duplexing|transcript_malleability -
Affected files:
challenger/src/multi_field_challenger.rs,field/src/helpers.rs -
Violated invariant: The Fiat-Shamir sponge must bind challenges to the exact sequence of observed field elements. Specifically: (1) absorption must be injective — distinct observation streams must produce distinct sponge states, (2) squeezing must be injective — distinct PF rate cells must yield distinct F challenge sequences, and (3) all bits of each absorbed PF element must influence the sponge state.
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Exploit scenario: An attacker controlling prover-side observations can craft distinct transcripts that produce identical challenges, breaking the binding property of Fiat-Shamir. Three independent attack vectors exist:
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Partial-chunk aliasing (absorb):
duplexing()packsinput_buffer.chunks(num_f_elms)viareduce_32(base 2^32) with no length marker and no zeroing of unused rate slots. Observing[x]followed by a sample yields the same sponge state as[x, 0, ..., 0](padded tonum_f_elms) followed by a sample, sincereduce_32treats missing high limbs identically to explicit zeros. The attacker can extend or truncate the tail of any observation batch without changing future challenges. -
Non-injective squeeze (squeeze):
split_32decomposes each PF rate cell into base-2^64 digits and maps each throughTF::from_u64, which reduces modF::ORDER(~2^31). Two distinct PF values whose base-2^64 digits differ only in their upper 33 bits produce identical F challenge sequences. This weakens the entropy of sampled challenges and can enable selective forgery when the attacker can influence the sponge state pre-squeeze. -
High-bit truncation (observe Hash/MerkleCap):
num_f_elms = PF::bits() / 64computes the number of F limbs per PF element. For BN254 (254-bit field), this yields 3 limbs covering 192 bits — the top 62 bits of every digest word are silently discarded. An attacker can find two distinct BN254 hash digests that differ only in bits 192–253 and observe them interchangeably without affecting challenges.
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Evidence: In
duplexing(), the absorb path (reduce_32with base 2^32) and the squeeze path (split_32with base 2^64) use incompatible radices with no length domain separation.reduce_32is a plain Horner foldacc * 2^32 + digitwith no padding or tag, so trailing zeros are free.split_32extracts u64 digits and casts each viaTF::from_u64, which performs modular reduction, collapsing the top bits. The limb countPF::bits() / 64is a floor division that silently drops all bits beyond64 * num_f_elmsfor fields whose bit-width is not a multiple of 64.
Patches
Included in v0.4.3 and v0.5.3
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | p3-challenger | all versions | 0.4.3 |
| 🦀crates.io | p3-challenger | ≥ 0.5.0&&< 0.5.3 | 0.5.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for p3-challenger. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update p3-challenger to 0.4.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-vj64-rjf3-w3v7 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-vj64-rjf3-w3v7 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-vj64-rjf3-w3v7. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-vj64-rjf3-w3v7 in your dependencies?
O3 detects GHSA-vj64-rjf3-w3v7 across crates.io dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.