# CVE-2021-45709: Use of a Broken or Risky Cryptographic Algorithm in crypto2

> An unaligned memory read in the crypto2 crate can cause a crash during Chacha20 operations, leading to denial of service.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 26 Dec 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-9hfg-pxr6-q4vp, GHSA-pmcv-mgcf-rvxg, RUSTSEC-2021-0121

## What is CVE-2021-45709?

CVE-2021-45709 is a critical memory corruption vulnerability in n/a, published on 26 Dec 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2021-45709?

5 open source packages ship an affected version, including crypto2. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `crypto2` | crates.io | All versions to 0.1.2 | None |
| `crypto2` | crates.io | All versions to 0.1.2 | None |
| `crypto2` | crates.io | All versions to 0.1.2 | None |
| `crypto2` | crates.io | All versions to 0.1.2 | None |
| `crypto2` | crates.io | From 0.0.0-0 | None |

Products: Crypto2 Project Crypto2.

## How do I fix CVE-2021-45709?

No fix has been published for CVE-2021-45709 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-45709 being exploited?

There is no known exploitation of CVE-2021-45709 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-45709 and fix it if it is affected.

What it is: CVE-2021-45709 is a critical memory corruption vulnerability in n/a, published on 26 Dec 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-45709 in the wild and no public exploit code.

Affected packages and fixed versions:
- crypto2 (crates.io): affected all versions up to 0.1.2; no fix listed
- crypto2 (crates.io): affected all versions up to 0.1.2; no fix listed
- crypto2 (crates.io): affected all versions up to 0.1.2; no fix listed
- crypto2 (crates.io): affected all versions up to 0.1.2; no fix listed
- crypto2 (crates.io): affected from 0.0.0-0; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-45709/ (Markdown: https://insights.sbomify.com/CVE-2021-45709/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-45709
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-45709
- OSV: https://osv.dev/vulnerability/CVE-2021-45709

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-45709/
Summaries are generated and may contain mistakes; the official description above is the record.