# OSV-2026-860: UNKNOWN READ in write_publickey

> An unknown read error in write_publickey can cause a crash, potentially leading to denial of service in applications using the affected library.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not stated
- **Attackable:** Not stated
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 6 Jun 2026

## What is OSV-2026-860?

OSV-2026-860 is a memory corruption vulnerability in opensc, published on 6 Jun 2026. 

### Official description

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=519999729

```
Crash type: UNKNOWN READ
Crash state:
write_publickey
auth_update_binary
sc_update_binary
```

## Which versions are affected by OSV-2026-860?

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


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

## How do I fix OSV-2026-860?

No fix has been published for OSV-2026-860 yet. Limit exposure of the affected software until one is available.

## Is OSV-2026-860 being exploited?

There is no known exploitation of OSV-2026-860 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for OSV-2026-860 and fix it if it is affected.

What it is: OSV-2026-860 is a memory corruption vulnerability in opensc, published on 6 Jun 2026. 
Exploitation: There is no known exploitation of OSV-2026-860 in the wild and no public exploit code.

Affected packages and fixed versions:
- opensc (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-2026-860/ (Markdown: https://insights.sbomify.com/OSV-2026-860/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/OSV-2026-860

---
From sbomify Insights: https://insights.sbomify.com/OSV-2026-860/
Summaries are generated and may contain mistakes; the official description above is the record.