Bug 2553049 (CVE-2026-110932)
| Summary: | CVE-2026-110932 keycloak-services: keycloak-services: Unauthenticated persistent disk exhaustion via theme gzip cache | ||
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| Product: | [Other] Security Response | Reporter: | OSIDB Bzimport <bzimport> |
| Component: | vulnerability | Assignee: | Product Security <prodsec-ir-bot> |
| Status: | NEW --- | QA Contact: | |
| Severity: | high | Docs Contact: | |
| Priority: | high | ||
| Version: | unspecified | CC: | aschwart, aszczucz, boliveir, drichtar, mposolda, pjindal, rmartinc, security-response-team, ssilvert, sthorger, vmuzikar |
| Target Milestone: | --- | Keywords: | Security |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | --- | |
| Doc Text: |
A flaw was found in the theme resource endpoint of Keycloak, an open-source identity and access management solution. The issue occurs because the server fails to validate theme names before using them as keys for an on-disk gzip cache. An unauthenticated attacker can exploit this by sending many requests with unique, fabricated theme names, leading to persistent disk space exhaustion that survives server restarts and causes service disruptions.
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | Type: | --- | |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Deadline: | 2027-01-11 | ||
A Resource Exhaustion vulnerability was found in Keycloaks theme resource endpoint (/resources/{version}/{themeType}/{themeName}/{path}). The root cause is improper validation of the themeName parameter when theme caching is enabled and the client requests gzip encoding. While the server resolves unknown theme names to a default theme, it uses the attacker-provided name to create a permanent file in the data/tmp/kc-gzip-cache/ directory. Because these entries are never expired or bounded, an unauthenticated remote attacker can send a high volume of requests with unique theme names to fill the servers disk. Successful exploitation leads to a persistent Denial of Service where legitimate theme assets return 404 errors and other disk-dependent operations, such as logging and transaction processing, fail.