CVE-2021-45709

Use of a Broken or Risky Cryptographic Algorithm in crypto2

9.8 Critical

An issue was discovered in the crypto2 crate through 2021-10-08 for Rust. During Chacha20 encryption and decryption, an unaligned read of a u32 may occur.

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

0.78%Up 0.2 points since Dec 27, 2021

What each source reports

NVD Score used 9.8

An issue was discovered in the crypto2 crate through 2021-10-08 for Rust. During Chacha20 encryption and decryption, an unaligned read of a u32 may occur.

Record: CVE-2021-45709
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0: 7.5 HighAV:N/AC:L/Au:N/C:P/I:P/A:P
Weakness: CWE-119
Updated: 2026-11-02

CVE List No score

An issue was discovered in the crypto2 crate through 2021-10-08 for Rust. During Chacha20 encryption and decryption, an unaligned read of a u32 may occur.

Record: CVE-2021-45709
Updated: 2026-11-02

EUVDEUVD-2022-0545 No score

An issue was discovered in the crypto2 crate through 2021-10-08 for Rust. During Chacha20 encryption and decryption, an unaligned read of a u32 may occur.

Record: EUVD-2022-0545
Updated: 2026-11-03

GitHub AdvisoriesGHSA-9hfg-pxr6-q4vp 9.8

Use of a Broken or Risky Cryptographic Algorithm in crypto2

The implementation does not enforce alignment requirements on input slices while incorrectly assuming 4-byte alignment through an unsafe call to std::slice::from_raw_parts_mut, which breaks the contract and introduces undefined behavior.