PatchTheCVECVE-2021-45709: An issue was discovered in the crypto2 crate through 2021-10-08 for Rust
CVE-2021-45709 is a critical-severity flaw (CVSS 9.8) affecting crypto2. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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.
Why this priority
- Critical severity
- Remotely exploitable, no login, no user action
No fix is published yet: follow the downgrade or mitigation steps.
Risk facts
| CVSS score | 9.8 (Critical) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.8% (top 44%) |
| CISA exploited list | No |
| Weakness | CWE-119 |
| Published | 2021-12-27 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2021-45709?
crypto2: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2021-45709 being exploited?
CVE-2021-45709 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2021-45709 affect?
CVE-2021-45709 affects crypto2. Severity is critical (CVSS 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.
How urgent is CVE-2021-45709?
Priority 53/100. Critical severity; Remotely exploitable, no login, no user action