How severe is CVE-2026-42875?

No CVSS score has been assigned to CVE-2026-42875 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-42875?

CVE-2026-42875 affects the following packages: github.com/external-secrets/external-secrets (Go). Ecosystems affected: Go.

How do I fix CVE-2026-42875?

Update github.com/external-secrets/external-secrets to 2.4.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-42875 is resolved across your whole dependency graph.

How do I detect CVE-2026-42875 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/external-secrets/external-secrets, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-42875 if there is no patch (or I can't update yet)?

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.

Is CVE-2026-42875 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-42875 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-2026-42875?

CVE-2026-42875 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 15th 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-2026-42875?

CVE-2026-42875 is classified as CWE-285 (CWE-285), CWE-668 (CWE-668). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-42875 published, and has it been updated?

CVE-2026-42875 was published on May 11, 2026 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

CVE-2026-42875 — external-secrets

CVE-2026-42875 is a CWE-285 vulnerability in github.com/external-secrets/external-secrets. A fix is available for github.com/external-secrets/external-secrets — see the affected versions and patch details below.

External Secrets Operator: Namespace Isolation Bypass in CAProvider ConfigMap Resolution for SecretStore

Also known asGHSA-wv26-88m5-6h59GO-2026-5723

Published

May 11, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 10, 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.
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 CVE-2026-42875.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs15th percentile — riskier than 15% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐹github.com/external-secrets/external-secrets

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

Namespaced SecretStore resources that used CAProvider with type ConfigMap could resolve CA material from another namespace when caProvider.namespace was set. This bypassed the namespace boundary enforced for SecretStore-backed references in providers that rely on the shared runtime CA resolver.

The accessible data is used as CA validation material, hence it is not directly exposed.

Impact:

Direct data exfiltration risk: low
Existence disclosure: an attacker can infer whether a target ConfigMap/key exists in another namespace.
Trust-boundary violation: a tenant can make its SecretStore consume CA material owned by another namespace.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/external-secrets/external-secrets`	all versions	2.4.0`go get github.com/external-secrets/external-secrets@v2.4.0`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/external-secrets/external-secrets, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/external-secrets/external-secrets to 2.4.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-42875 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.

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 HatImportant

Red Hat rates this flaw as Moderate. The exposed data is limited to CA certificate material, which is public-key content used for TLS validation, not secrets or credentials. An attacker cannot leverage this to access the actual secrets stored in the external backend. Exploitation requires permissions to create or…

Workaround published by Red Hat

Do not set the caProvider.namespace field on namespaced SecretStore resources. When this field is omitted, the operator resolves CA material only from the local namespace, preventing the cross-namespace bypass. Review existing SecretStore configurations and remove any caProvider.namespace references that are not strictly required.

Source: Red Hat security advisory for CVE-2026-42875 (CC BY 4.0)

Frequently Asked Questions

### Impact Namespaced SecretStore resources that used CAProvider with type `ConfigMap` could resolve CA material from another namespace when `caProvider.namespace` was set. This bypassed the namespace boundary enforced for SecretStore-backed references in providers that rely on the shared runtime CA resolver. The accessible data is used as CA validation material, hence it is not directly exposed. Impact: - Direct data exfiltration risk: low - Existence disclosure: an attacker can infer whether a target ConfigMap/key exists in another namespace. - Trust-boundary violation: a tenant can mak

O3 Security · Impact-Aware SCA

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