How severe is CVE-2022-23635?

CVE-2022-23635 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2022-23635?

CVE-2022-23635 affects the following packages: istio.io/istio (Go), istio.io/istio (Go), istio.io/istio (Go). Ecosystems affected: Go.

How do I fix CVE-2022-23635?

Update istio.io/istio to 1.13.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-23635 is resolved across your whole dependency graph.

How do I detect CVE-2022-23635 in my Go dependencies?

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.

How do I mitigate CVE-2022-23635 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is CVE-2022-23635 actively exploited in the wild?

No public exploit code has been indexed for CVE-2022-23635 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2022-23635?

CVE-2022-23635 has an EPSS (Exploit Prediction Scoring System) score of 1.7%, placing it in the 77th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2022-23635?

CVE-2022-23635 is classified as Improper Authentication (CWE-287), CWE-1284 (CWE-1284). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2022-23635 published, and has it been updated?

CVE-2022-23635 was published on February 22, 2022 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

HIGH severity

CVE-2022-23635 — istio

HIGHFix: istio/istio@5f3b5ed

CVE-2022-23635 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

Also known asGHSA-856q-xv3c-7f2f

Published

Feb 22, 2022

Updated

Oct 28, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Nov 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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 CVE-2022-23635.

EPSS Exploitation Probability

via FIRST.org ↗

1.7%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs77th percentile — riskier than 77% of all scored CVEsHighest risk

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

3 pkgs affected

🐹istio.io/istio🐹istio.io/istio🐹istio.io/istio

Real-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

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`istio.io/istio`	≥ 1.13.0&&< 1.13.1	1.13.1`go get istio.io/istio@v1.13.1`
🐹Go	`istio.io/istio`	≥ 1.12.0&&< 1.12.4	1.12.4`go get istio.io/istio@v1.12.4`
🐹Go	`istio.io/istio`	all versions	1.11.7`go get istio.io/istio@v1.11.7`

Affected Products

1 product · 3 configurations

Application

istioistio

≥ 1.13.0 && < 1.13.1

range

Detection & mitigation playbook

Open-source dependency

Detect
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 CVE-2022-23635 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

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.

Red HatModerate

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

### 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](https://istio.io/latest/docs/setup/install/multicluster/primary-remote/) topologies, this port is exposed over the publi