Algorithms compute incorrect results in blake2

published 2019-08-25 7y ago modified 2026-06-17 4mo ago also GHSA-4x25-pvhw-5224 , RUSTSEC-2019-0019 , EUVD-2021-1566

cvss: 9.8; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.9%; EPSS 0.9% chance of exploitation in 30 days, percentile 60%
public exploits: 0; none known

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.

Patch / fix

fixed in 2

crates.io blake2 0.8.1
blake2 blake2-rust 0.8.1

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Exploit prediction

0.93% chance of exploitation in the next 30 days, higher than 60% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
NVD	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD	2.0	7.5	AV:N/AC:L/Au:N/C:P/I:P/A:P
OSV	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
GitHub	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem	package	affected	fixed in
crates.io	blake2	<0.8.1 >=0.0.0-0, <0.8.1	0.8.1

Classification

Weakness

CWE-327 Use of a Broken or Risky Cryptographic Algorithm

References

rustsec.org /advisories/RUSTSEC-2019-0019.html
web, third-party-advisory, advisory
nvd.nist.gov /vuln/detail/CVE-2019-16143
advisory
github.com /RustCrypto/MACs/issues/19
web, report
github.com /RustCrypto/hashes/tree/master/blake2
package
crates.io /crates/blake2
package

Sources

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