# CVE-2024-21502: Uninitialized Variable in fastecdsa

> An attacker can cause denial of service in the fastecdsa library by exploiting an uninitialized variable vulnerability that leads to memory corruption.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Feb 2024
- **Updated:** 1 Nov 2024
- **Also known as:** GHSA-ph86-g9r3-5qw4, PYSEC-2024-39

## What is CVE-2024-21502?

CVE-2024-21502 is a high-severity memory corruption vulnerability in fastecdsa, published on 24 Feb 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Versions of the package fastecdsa before 2.3.2 are vulnerable to Use of Uninitialized Variable on the stack, via the curvemath_mul function in src/curveMath.c, due to being used and interpreted as user-defined type. Depending on the variable's actual value it could be arbitrary free(), arbitrary realloc(), null pointer dereference and other. Since the stack can be controlled by the attacker, the vulnerability could be used to corrupt allocator structure, leading to possible heap exploitation. The attacker could cause denial of service by exploiting this vulnerability.

Weakness: CWE-908 (Use of Uninitialized Resource), CWE-457 (Use of Uninitialized Variable)

## Which versions are affected by CVE-2024-21502?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `fastecdsa` | PyPI | All versions | 2.3.2 |
| `fastecdsa` | PyPI | All versions | 2.3.2 |
| `fastecdsa` | PyPI | All versions | 2.3.2 |

Products: Antonkueltz Fastecdsa.

## How do I fix CVE-2024-21502?

Upgrade fastecdsa to 2.3.2 or later.

## Is CVE-2024-21502 being exploited?

There is no known exploitation of CVE-2024-21502 in the wild and no public exploit code.

## Other vulnerabilities in fastecdsa

- [CVE-2020-12607](https://insights.sbomify.com/CVE-2020-12607/): Improper Verification of Cryptographic Signature in fastecdsa (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-21502 and fix it if it is affected.

What it is: CVE-2024-21502 is a high-severity memory corruption vulnerability in fastecdsa, published on 24 Feb 2024. 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-2024-21502 in the wild and no public exploit code.

Affected packages and fixed versions:
- fastecdsa (PyPI): affected all versions; fixed in 2.3.2
- fastecdsa (PyPI): affected all versions; fixed in 2.3.2
- fastecdsa (PyPI): affected all versions; fixed in 2.3.2

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-2024-21502/ (Markdown: https://insights.sbomify.com/CVE-2024-21502/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-21502
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-21502
- OSV: https://osv.dev/vulnerability/CVE-2024-21502

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-21502/
Summaries are generated and may contain mistakes; the official description above is the record.