CVE-2026-88899 knowns before 0.31.0 External Control of Agent Working Directory via x-opencode-directory Header
Critical 9.3
Published
Updated
Check this codebase for CVE-2026-88899 and fix it if it is affected.
What it is: CVE-2026-88899 is a critical vulnerability in knowns-dev knowns, published on 10 Sep 2026.
Exploitation: There is no known exploitation of CVE-2026-88899 in the wild and no public exploit code.
Affected product: knowns-dev knowns. No package-level version data is available, so check the vendor advisory linked from the reference page.
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-2026-88899/ (Markdown: https://insights.sbomify.com/CVE-2026-88899/index.md)
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-88899?
CVE-2026-88899 is a critical vulnerability in knowns-dev knowns, published on 10 Sep 2026.
Official description
knowns versions before 0.31.0 fail to properly validate the x-opencode-directory request header in the /api/opencode proxy endpoint. Remote attackers can supply arbitrary directory paths to execute file operations outside the project root on the host system.
Weakness: CWE-73
Which versions are affected by CVE-2026-88899?
How do I fix CVE-2026-88899?
No fix has been published for CVE-2026-88899 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-88899 being exploited?
There is no known exploitation of CVE-2026-88899 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as GHSA-9h2q-r9fh-f98w.