RUSTSEC-2026-0208
Potential Panic in AVX2 SHAKE-256
The AVX2-optimized implementation of SHAKE-256 intended for use in ML-KEM and ML-DSA would panic if the length of the output buffers was greater than 32 and not a multiple of 8, due to an out-of-bounds indexing operation.
Impact
This bug impacts users on AVX2 platforms that use the
libcrux_sha3::avx2::x4::shake256 API outside of ML-KEM or ML-DSA
with output buffers of length > 32 and not divisible by 8. It does
not impact the use in ML-KEM or ML-DSA because there output buffer
lengths are always divisible by 8.
Mitigation
Starting from version 0.0.10, the AVX2-optimized SHAKE-256 will no
longer panic on output buffer lengths > 32 that are not divisible by
8.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
What each source reports
OSV Score used
Potential Panic in AVX2 SHAKE-256
The AVX2-optimized implementation of SHAKE-256 intended for use in ML-KEM and ML-DSA would panic if the length of the output buffers was greater than 32 and not a multiple of 8, due to an out-of-bounds indexing operation.
Impact
This bug impacts users on AVX2 platforms that use the
libcrux_sha3::avx2::x4::shake256 API outside of ML-KEM or ML-DSA
with output buffers of length > 32 and not divisible by 8. It does
not impact the use in ML-KEM or ML-DSA because there output buffer
lengths are always divisible by 8.
Mitigation
Starting from version 0.0.10, the AVX2-optimized SHAKE-256 will no
longer panic on output buffer lengths > 32 that are not divisible by
8.
- Record
RUSTSEC-2026-0208- CVSS 4.0
- 8.2 High
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Updated
- 2026-11-02
Affected packages
| Package | Affected | Fixed |
|---|---|---|
libcrux-sha3crates.io |
0.0.0-0 up to 0.0.10 | 0.0.10 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
RUSTSEC-2026-0208 is a high vulnerability (CVSS 8.2) in libcrux-sha3, published May 21, 2026. No source lists public exploit code. Fixed in libcrux-sha3 0.0.10.