RUSTSEC-2026-0329
Auto-Reseeding HMAC-DRBG could panic for some output lengths
The automatically reseeding implementations of HMAC-DRBG would panic if called with a desired non-zero output length cleanly divisible by 65_536, the maximum number of output bytes that can be generated before reseeding has to happen.
Impact
An application relying on libcrux-hmac-drgb to provide randomness of byte length a non-zero integer multiple of 65_536 in a single call to fill_bytes would panic.
Any calls with output buffer lengths not cleanly divisible by 65_536 are not affected.
Mitigation
With release the release of version 0.0.2 of libcrux-hmac-drbg this bug has been fixed and reseeding DRBG implementations can be used with arbitrary output lengths.
We recommend users upgrade to libcrux-hmac-drbg version 0.0.2.
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
Auto-Reseeding HMAC-DRBG could panic for some output lengths
The automatically reseeding implementations of HMAC-DRBG would panic if called with a desired non-zero output length cleanly divisible by 65_536, the maximum number of output bytes that can be generated before reseeding has to happen.
Impact
An application relying on libcrux-hmac-drgb to provide randomness of byte length a non-zero integer multiple of 65_536 in a single call to fill_bytes would panic.
Any calls with output buffer lengths not cleanly divisible by 65_536 are not affected.
Mitigation
With release the release of version 0.0.2 of libcrux-hmac-drbg this bug has been fixed and reseeding DRBG implementations can be used with arbitrary output lengths.
We recommend users upgrade to libcrux-hmac-drbg version 0.0.2.
- Record
RUSTSEC-2026-0329- 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-hmac-drbgcrates.io |
0.0.0-0 up to 0.0.2 | 0.0.2 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
RUSTSEC-2026-0329 is a high vulnerability (CVSS 8.2) in libcrux-hmac-drbg, published August 3, 2026. No source lists public exploit code. Fixed in libcrux-hmac-drbg 0.0.2.