Rust advisories / libcrux-hmac-drbg
VulnerabilityRUSTSEC-2026-0329 · libcrux-hmac-drbg
RUSTSEC-2026-0329: Auto-Reseeding HMAC-DRBG could panic for some output lengths
Short answerA security vulnerability in the libcrux-hmac-drbg crate: Auto-Reseeding HMAC-DRBG could panic for some output lengths. No severity score was published. Fixed in 0.0.2: update to a fixed version.
| Crate | libcrux-hmac-drbg |
|---|---|
| Type | Vulnerability |
| Affected versions | Before 0.0.2. |
| Fixed in | 0.0.2 |
| Severity | not scored 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 |
| Published | 2026-08-03 |
| Last changed | 2026-10-07 |
| Also known as | none |
| Affected functions | libcrux_hmac_drbg::HmacDrbgRng::fill_bytes |
What to do
- See which version you have:
cargo tree -i libcrux-hmac-drbg(it also shows which of your dependencies pulls it in). - Update within your version requirement:
cargo update -p libcrux-hmac-drbg. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for examplelibcrux-hmac-drbg = "0.0.2") or update the dependency that pulls it in. - Check again with
cargo audit, or paste your Cargo.lock into our Cargo.toml checker.
Details from the advisory
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.
References
- Package: crates.io/crates/libcrux-hmac-drbg
- Advisory: rustsec.org/advisories/RUSTSEC-2026-0329.html
- Web: github.com/celabshq/libcrux/pull/1558
From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.
Up next
Are you affected?Check your whole dependency treePaste Cargo.lock: every advisory, for your exact versions.Read it next →Also worth your time
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