Contras Affected by CopyFile Policy Subversion via SymlinksGHSA-rh99-wc69-c255
HIGHGHSA-rh99-wc69-c255 is a high-severity (CVSS 8.1) CWE-59 vulnerability in github.com/edgelesssys/contrast. A fix is available for github.com/edgelesssys/contrast — see the affected versions and patch details below.
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-rh99-wc69-c255.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
github.com/edgelesssys/contrastReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Impact
The Kata agent policies generated by the Contrast CLI had an issue in the CopyFile verification, which allowed arbitrary writes to the guest root filesytem. A malicious process on the host with the capability to connect to the Kata agent VSOCK could connect to the agent and issue a series of CopyFile requests to overwrite security-critical files or trick the workload into disclosing sensitive data, which effectively amounts to a full guest takeover.
Patches
This issue has been patched in Contrast v1.19.1.
Note that this fix does not change the fact that host-provided content is generally not trustworthy, as documented.
Workarounds
If upgrading is not possible, users can implement the fix in rego and pass it to contrast generate --policy. The rego-only fix is a bit trickier than the patch, because the data to check is binary. See the references for details.
Resources
- Upstream GHSA: https://github.com/kata-containers/kata-containers/security/advisories/GHSA-q49m-57vm-c8cc
- Alternative policy-only fix: https://gist.github.com/burgerdev/304dd0ab0fff1665b7c27e18a30cf96e
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/edgelesssys/contrast | all versions | 1.19.1go get github.com/edgelesssys/contrast@v1.19.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/edgelesssys/contrast, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/edgelesssys/contrast to 1.19.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-rh99-wc69-c255 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is GHSA-rh99-wc69-c255 in your dependencies?
Find it across Go, including transitive dependencies.