ZDF
Sign inSign up

Vulnerabilities

Vulnerability · CVE-2026-0976

A flaw was found in Keycloak.

Published Jan 15, 2026 · catalog updated Oct 23, 2026 · A flaw was found

Last checked Oct 25, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-0976. EPSS is 0.45%. Act only if a listed version of A flaw was found is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (A flaw was found).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Low3.7
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.45%
Remediation
Advisory link
Affected products
Maven org.keycloak:keycloak-quarkus-server

A flaw was found in Keycloak. This improper input validation vulnerability occurs because Keycloak accepts RFC-compliant matrix parameters in URL path segments, while common reverse proxy configurations may ignore or mishandle them. A remote attacker can craft requests to mask path segments, potentially bypassing proxy-level path filtering. This could expose administrative or sensitive endpoints that operators believe are not externally reachable.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • Maven org.keycloak:keycloak-quarkus-server0 → 26.2.5

How to fix CVE-2026-0976

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-0976. EPSS is 0.45%. Act only if a listed version of A flaw was found is installed.

Which versions are affected?

Compare what you have installed with 0 → 26.2.5. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-20: Improper Input Validation. EPSS 0.45%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Jan 15, 2026 · NIST NVD

    Detected

    A flaw was found in Keycloak. This improper input validation vulnerability occurs because Keycloak accepts RFC-compliant matrix parameters in URL path segments, while common reverse proxy configurations may ignore or mishandle them. A remote attacker can craft requests to mask path segments, potentially bypassing proxy-level path filtering. This could expose administrative or sensitive endpoints t

  2. Oct 22, 2026 · NIST NVD

    Updated

    A flaw was found in Keycloak. This improper input validation vulnerability occurs because Keycloak accepts RFC-compliant matrix parameters in URL path segments, while common reverse proxy configurations may ignore or mishandle them. A remote attacker can craft requests to mask path segments, potentially bypassing proxy-level path filtering. This could expose administrative or sensitive endpoints t

  3. Oct 23, 2026 · GitHub Advisory Database

    Fix available

    org.keycloak:keycloak-quarkus-server fixed in 26.2.5

  4. Oct 23, 2026 · GitHub Advisory Database

    Updated

    A flaw was found in Keycloak. This improper input validation vulnerability occurs because Keycloak accepts RFC-compliant matrix parameters in URL path segments, while common reverse proxy configurations may ignore or mishandle them. A remote attacker can craft requests to mask path segments, potentially bypassing proxy-level path filtering. This could expose administrative or sensitive endpoints t

Sources

  • CVE.orgVulnerability recordCVE-2026-0976

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-0976

    30-day exploitation probability 0.45%

    first.org
  • GitHub Advisory DatabasePackage advisoryGHSA-v897-pv23-r8cw

    GitHub Advisory Database record mirrored by OSV.

    github.com
  • GitLab Advisory DatabasePackage advisorymaven/org.keycloak/keycloak-quarkus-server/CVE-2026-0976.yml

    A flaw was found in Keycloak. This improper input validation vulne attacker can craft requests to mask path segments, potentially bypassing proxy-level path filtering. This could expose administrative or sensitive endpoints that operators believe are not externally reachable." -date: "2026-01-15" +date: "2026-10-23" pubdate: "2026-01-15" affected_range: "[,26.2.5]" fixed_versions: [] @@ -23,7 +23,

    gitlab.com
  • NIST NVDVulnerability recordCVE-2026-0976

    A flaw was found in Keycloak. This improper input validation vulnerability occurs because Keycloak accepts RFC-compliant matrix parameters in URL path segments, while common reverse proxy configurations may ignore or mishandle them. A remote attacker can craft requests to mask pa

    nvd.nist.gov
  • OpenSSF OSV / OSV ScannerPackage advisoryGHSA-v897-pv23-r8cw

    Keycloak has an improper input validation vulnerability

    osv.dev

References

Freshness

Last verified in this catalog Oct 23, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • GitHub Advisory DatabaseOct 25, 2026
  • OpenSSF OSV / OSV ScannerOct 25, 2026
  • GitLab Advisory DatabaseOct 23, 2026
  • FIRST EPSSOct 23, 2026
  • CVE.orgOct 23, 2026
  • NIST NVDOct 23, 2026