CVE-2019-16143
Algorithms compute incorrect results in blake2
An issue was discovered in the blake2 crate before 0.8.1 for Rust. The BLAKE2b and BLAKE2s algorithms, when used with HMAC, produce incorrect results because the block sizes are half of the required sizes.
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
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
An issue was discovered in the blake2 crate before 0.8.1 for Rust. The BLAKE2b and BLAKE2s algorithms, when used with HMAC, produce incorrect results because the block sizes are half of the required sizes.
- Record
CVE-2019-16143- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 7.5 High
AV:N/AC:L/Au:N/C:P/I:P/A:P - Weakness
- CWE-327
- Updated
- 2026-11-02
CVE List No score
An issue was discovered in the blake2 crate before 0.8.1 for Rust. The BLAKE2b and BLAKE2s algorithms, when used with HMAC, produce incorrect results because the block sizes are half of the required sizes.
- Record
CVE-2019-16143- Updated
- 2026-11-02
EUVDEUVD-2021-1566 No score
An issue was discovered in the blake2 crate before 0.8.1 for Rust. The BLAKE2b and BLAKE2s algorithms, when used with HMAC, produce incorrect results because the block sizes are half of the required sizes.
- Record
EUVD-2021-1566- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-4x25-pvhw-5224
Algorithms compute incorrect results in blake2
An issue was discovered in the blake2 crate before 0.8.1 for Rust. The BLAKE2b and BLAKE2s algorithms, when used with HMAC, produce incorrect results because the block sizes are half of the required sizes.
- Record
GHSA-4x25-pvhw-5224- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-327
- Updated
- 2026-11-02
OSVGHSA-4x25-pvhw-5224
Algorithms compute incorrect results in blake2
An issue was discovered in the blake2 crate before 0.8.1 for Rust. The BLAKE2b and BLAKE2s algorithms, when used with HMAC, produce incorrect results because the block sizes are half of the required sizes.
- Record
GHSA-4x25-pvhw-5224- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-327
- Updated
- 2026-11-02
OSVRUSTSEC-2019-0019
HMAC-BLAKE2 algorithms compute incorrect results
When used in conjunction with the Hash-based Message Authentication Code (HMAC),
the BLAKE2b and BLAKE2s implementations in blake2 crate versions prior to
v0.8.1 used an incorrect block size (32-bytes instead of 64-bytes for BLAKE2s,
and 64-bytes instead of 128-bytes for BLAKE2b), causing them to miscompute the
MacResult.
The v0.8.1 release of the blake2 crate uses the correct block sizes.
Note that this advisory only impacts usage of BLAKE2 with HMAC, and does not
impact Digest functionality.
- Record
RUSTSEC-2019-0019- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Affected products
Affected packages
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2019-16143 is a critical vulnerability (CVSS 9.8) in Blake2 Blake2-rust, published August 25, 2019. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.93%, the 60th percentile. Fixed in blake2 0.8.1.