OSV-2026-1220 Use-of-uninitialized-value in str_escape
Not scored
Published
Check this codebase for OSV-2026-1220 and fix it if it is affected.
What it is: OSV-2026-1220 is a vulnerability in mruby, published on 31 Aug 2026.
Exploitation: There is no known exploitation of OSV-2026-1220 in the wild and no public exploit code.
Affected packages and fixed versions:
- mruby (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-2026-1220/ (Markdown: https://insights.sbomify.com/OSV-2026-1220/index.md)
An attacker could trigger a crash in the Ruby VM via uninitialized value usage in string escaping, potentially causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not stated
- Attackable
- Not stated
- Victim action needed
- Not stated
- Fix
- None listed
What is OSV-2026-1220?
OSV-2026-1220 is a vulnerability in mruby, published on 31 Aug 2026.
Official description
OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=554268877
Crash type: Use-of-uninitialized-value
Crash state:
str_escape
mrb_vm_exec
yield_with_attr
Which versions are affected by OSV-2026-1220?
1 open source package ship an affected version, including mruby.
| Package | Affected | Fixed in |
|---|---|---|
mruby OSS-Fuzz | All versions | None |
How do I fix OSV-2026-1220?
No fix has been published for OSV-2026-1220 yet. Limit exposure of the affected software until one is available.
Is OSV-2026-1220 being exploited?
There is no known exploitation of OSV-2026-1220 in the wild and no public exploit code.