GHSA-856q-xv3c-7f2f is a high-severity (CVSS 7.5) Improper Authentication vulnerability in istio.io/istio. A fix is available for istio.io/istio — see the affected versions and patch details below.
Unauthenticated control plane denial of service attack in Istio
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- 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-856q-xv3c-7f2f.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-856q-xv3c-7f2f plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 379,145 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
istio.io/istio🐹istio.io/istio🐹istio.io/istioReal-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 Istio control plane, istiod, is vulnerable to a request processing error, allowing a malicious attacker that sends a specially crafted message which results in the control plane crashing. This endpoint is served over TLS port 15012, but does not require any authentication from the attacker.
For simple installations, Istiod is typically only reachable from within the cluster, limiting the blast radius. However, for some deployments, especially multicluster topologies, this port is exposed over the public internet.
Patches
- Istio 1.13.1 and above
- Istio 1.12.4 and above
- Istio 1.11.7 and above
Workarounds
There are no effective workarounds, beyond upgrading. Limiting network access to Istiod to the minimal set of clients can help lessen the scope of the vulnerability to some extent.
References
More details can be found in the Istio Security Bulletin
For more information
If you have any questions or comments about this advisory, please email us at [email protected]
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | istio.io/istio | ≥ 1.13.0&&< 1.13.1 | 1.13.1go get istio.io/istio@v1.13.1 |
| 🐹Go | istio.io/istio | ≥ 1.12.0&&< 1.12.4 | 1.12.4go get istio.io/istio@v1.12.4 |
| 🐹Go | istio.io/istio | all versions | 1.11.7go get istio.io/istio@v1.11.7 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for istio.io/istio, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update istio.io/istio to 1.13.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-856q-xv3c-7f2f 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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-856q-xv3c-7f2f can be triaged on real exposure rather than presence alone.
Tailored to GHSA-856q-xv3c-7f2f. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
| Product | Fixed in | Advisory |
|---|---|---|
| OpenShift Service Mesh 2.0 | servicemesh-0:2.0.9-3.el8 | RHSA-2022:1276 |
| OpenShift Service Mesh 2.1 | servicemesh-0:2.1.2-4.el8 | RHSA-2022:1275 |
Frequently Asked Questions
Is GHSA-856q-xv3c-7f2f in your dependencies?
O3 Security finds GHSA-856q-xv3c-7f2f across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.