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Fencer Vulns
medium 6.8

CVE-2026-61795 json

Capsule: hostnameRegexHandler.OnUpdate validates stale (old) Tenant regex, allowing invalid AllowedHostnames regex to bypass webhook validation

published 2026-09-18 51 d ago modified 2026-09-28 41 d ago also GHSA-f94q-w3w8-cj67 , GO-2026-6519 , EUVD-2026-83166

cvss
6.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 48%
public exploits
0
none known

Summary

Capsule is a multi-tenancy and policy-based framework for Kubernetes. From 0.13.0 until 0.13.7, hostnameRegexHandler.OnUpdate in internal/webhook/tenant/validation/hostname_regex.go reverses the new and old Tenant parameters and validates the previous AllowedHostnames.Regex instead of the submitted value. A cluster administrator can therefore store a malformed AllowedHostnames.Regex after the webhook accepts the update based on stale valid state. Subsequent Ingress creation or update reaches validate_hostnames.go, which evaluates the malformed pattern, ignores the regular-expression error, and treats every hostname as unmatched, blocking Ingress operations for the affected tenant until an administrator repairs the Tenant configuration. This issue is fixed in version 0.13.7.

Patch / fix

  • go github.com/projectcapsule/capsule 0.13.7

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
51 d ago

Exploit prediction

0.59% chance of exploitation in the next 30 days, higher than 48% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.8 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H
GitHub 3.1 6.8 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
go github.com/projectcapsule/capsule
>=0.13.0, <0.13.7
0.13.7

Affected products

  • projectcapsule capsule

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.