# CVE-2021-45705: Aliased mutable references from `tls_rand` & `TlsWyRand`

> The nanorand Rust library allows multiple mutable references to the same object, potentially leading to memory corruption and undefined behavior.

- **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:** Yes
- **Published:** 26 Dec 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-p6gj-gpc8-f8xw, GHSA-r57r-j98g-587f, RUSTSEC-2021-0114

## What is CVE-2021-45705?

CVE-2021-45705 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 nanorand crate before 0.6.1 for Rust. There can be multiple mutable references to the same object because the TlsWyRand Deref implementation dereferences a raw pointer.

## Which versions are affected by CVE-2021-45705?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `nanorand` | crates.io | From 0.5.0 | 0.6.1 |
| `nanorand` | crates.io | From 0.5.0 | 0.6.1 |
| `nanorand` | crates.io | From 0.5.0 | 0.6.1 |
| `nanorand` | crates.io | From 0.5.0 | 0.6.1 |
| `nanorand` | crates.io | From 0.5.0 | 0.6.1 |

Products: Nanorand Project Nanorand.

## How do I fix CVE-2021-45705?

Upgrade nanorand to 0.6.1 or later.

## Is CVE-2021-45705 being exploited?

There is no known exploitation of CVE-2021-45705 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2020-35926](https://insights.sbomify.com/CVE-2020-35926/): Improper random number generation in nanorand (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-45705 and fix it if it is affected.

What it is: CVE-2021-45705 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-2021-45705 in the wild and no public exploit code.

Affected packages and fixed versions:
- nanorand (crates.io): affected from 0.5.0; fixed in 0.6.1
- nanorand (crates.io): affected from 0.5.0; fixed in 0.6.1
- nanorand (crates.io): affected from 0.5.0; fixed in 0.6.1
- nanorand (crates.io): affected from 0.5.0; fixed in 0.6.1
- nanorand (crates.io): affected from 0.5.0; fixed in 0.6.1

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-2021-45705/ (Markdown: https://insights.sbomify.com/CVE-2021-45705/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-45705
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-45705
- OSV: https://osv.dev/vulnerability/CVE-2021-45705

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-45705/
Summaries are generated and may contain mistakes; the official description above is the record.