OSV-2026-867 Bad-cast to std::__shared_weak_count from invalid vptr
Not scored
Published
Check this codebase for OSV-2026-867 and fix it if it is affected.
What it is: OSV-2026-867 is a memory corruption vulnerability in assimp, published on 7 Jun 2026.
Exploitation: There is no known exploitation of OSV-2026-867 in the wild and no public exploit code.
Affected packages and fixed versions:
- assimp (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-2026-867/ (Markdown: https://insights.sbomify.com/OSV-2026-867/index.md)
A bad cast vulnerability in the Assimp library can cause a crash when processing STEP files, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Not stated
- Victim action needed
- Not needed
- Fix
- None listed
What is OSV-2026-867?
OSV-2026-867 is a memory corruption vulnerability in assimp, published on 7 Jun 2026.
Official description
OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=520147546
Crash type: Bad-cast
Crash state:
Bad-cast to std::__shared_weak_count from invalid vptr
std::__1::shared_ptr<Assimp::STEP::EXPRESS::DataType const>::shared_ptr
Assimp::STEP::ReadFileHeader
Which versions are affected by OSV-2026-867?
1 open source package ship an affected version, including assimp.
| Package | Affected | Fixed in |
|---|---|---|
assimp OSS-Fuzz | All versions | None |
How do I fix OSV-2026-867?
No fix has been published for OSV-2026-867 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is OSV-2026-867 being exploited?
There is no known exploitation of OSV-2026-867 in the wild and no public exploit code.