# CVE-2020-35861: Out of bounds read in bumpalo

> Attackers can read unknown memory, potentially exposing cryptographic keys, via the realloc feature in the bumpalo Rust library.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 31 Dec 2020
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2020-35861, GHSA-vqx7-pw4r-29rr, RUSTSEC-2020-0006, UBUNTU-CVE-2020-35861

## What is CVE-2020-35861?

CVE-2020-35861 is a high-severity vulnerability in n/a, published on 31 Dec 2020. 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 bumpalo crate before 3.2.1 for Rust. The realloc feature allows the reading of unknown memory. Attackers can potentially read cryptographic keys.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2020-35861?

3 open source packages ship an affected version, including bumpalo. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `bumpalo` | crates.io | From 3.0.0 | 3.2.1 |
| `bumpalo` | crates.io | From 3.0.0 | 3.2.1 |
| `bumpalo` | crates.io | From 3.0.0 | 3.2.1 |

Products: Bumpalo Project Bumpalo.

## How do I fix CVE-2020-35861?

Upgrade bumpalo to 3.2.1 or later.

## Is CVE-2020-35861 being exploited?

There is no known exploitation of CVE-2020-35861 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-35861 and fix it if it is affected.

What it is: CVE-2020-35861 is a high-severity vulnerability in n/a, published on 31 Dec 2020. 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-2020-35861 in the wild and no public exploit code.

Affected packages and fixed versions:
- bumpalo (crates.io): affected from 3.0.0; fixed in 3.2.1
- bumpalo (crates.io): affected from 3.0.0; fixed in 3.2.1
- bumpalo (crates.io): affected from 3.0.0; fixed in 3.2.1

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-2020-35861/ (Markdown: https://insights.sbomify.com/CVE-2020-35861/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-35861
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-35861
- OSV: https://osv.dev/vulnerability/CVE-2020-35861

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-35861/
Summaries are generated and may contain mistakes; the official description above is the record.