# OSV-2018-195: Heap-buffer-overflow in gmp_emsa_pkcs1_signature_data

> A heap buffer overflow in the GMP library's PKCS1 signature verification allows attackers to cause crashes or potentially execute code via crafted signatures.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 13 Jan 2021

## What is OSV-2018-195?

OSV-2018-195 is a memory corruption vulnerability in strongswan, published on 13 Jan 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=10671

```
Crash type: Heap-buffer-overflow WRITE 1
Crash state:
gmp_emsa_pkcs1_signature_data
verify_emsa_pkcs1_signature
verify
```

## Which versions are affected by OSV-2018-195?

1 open source package ship an affected version, including strongswan.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `strongswan` | OSS-Fuzz | All versions | None |

## How do I fix OSV-2018-195?

No fix has been published for OSV-2018-195 yet. Limit exposure of the affected software until one is available.

## Is OSV-2018-195 being exploited?

There is no known exploitation of OSV-2018-195 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for OSV-2018-195 and fix it if it is affected.

What it is: OSV-2018-195 is a memory corruption vulnerability in strongswan, published on 13 Jan 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 OSV-2018-195 in the wild and no public exploit code.

Affected packages and fixed versions:
- strongswan (OSS-Fuzz): affected all versions; 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/OSV-2018-195/ (Markdown: https://insights.sbomify.com/OSV-2018-195/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/OSV-2018-195

---
From sbomify Insights: https://insights.sbomify.com/OSV-2018-195/
Summaries are generated and may contain mistakes; the official description above is the record.