CVE-2020-35509: A flaw was found in keycloak affecting versions 11.0.3 and 12.0.0

Routine

MEDIUM 5.4WATCHLISTDOWNGRADE

CVE-2020-35509 is a medium-severity flaw (CVSS 5.4) affecting keycloak. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A flaw was found in keycloak affecting versions 11.0.3 and 12.0.0. An expired certificate would be accepted by the direct-grant authenticator because of missing time stamp validations. The highest threat from this vulnerability is to data confidentiality and integrity.

Why this priority

On your watchlist

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.4% (top 71%)
CISA exploited list	No
Weakness	CWE-20, CWE-295
Published	2022-08-23
Last modified	2026-06-17

Publisher (CNA): Red Hat, Inc. · Vendor: redhat

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2022-08-23 16:15 UTCPublished CVE record published
2026-06-17 03:13 UTCUpdated Record last modified

redhat keycloak DOWNGRADE

Affected: 11.0.3 · 12.0.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 11.0.3

1. Check installed version

apt-cache policy keycloak || rpm -q keycloak || keycloak --version

2. No fixed release: DOWNGRADE to a release before 11.0.3 (Debian / Ubuntu)

apt-cache madison keycloak sudo apt install keycloak=<VERSION_BEFORE_11.0.3> sudo apt-mark hold keycloak

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list keycloak sudo dnf downgrade keycloak-<VERSION_BEFORE_11.0.3> sudo dnf versionlock add keycloak

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-35509?

keycloak: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-35509 being exploited?

CVE-2020-35509 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2020-35509 affect?

CVE-2020-35509 affects keycloak. Severity is medium (CVSS 5.4). A flaw was found in keycloak affecting versions 11.0.3 and 12.0.0. An expired certificate would be accepted by the direct-grant authenticator because of missing time stamp validations. The highest threat from this vulnerability is to data c

How urgent is CVE-2020-35509?

Priority 31/100. On your watchlist

Software pages

Keycloak vulnerabilities

Related CVEs

CVE-2023-6927 MEDIUM 4.6 MITIGATE DOWNGRADE A flaw was found in Keycloak
CVE-2023-6563 HIGH 7.7 UPGRADE DOWNGRADE An unconstrained memory consumption vulnerability was discovered in Keycloak
CVE-2023-6291 HIGH 7.1 UPGRADE DOWNGRADE A flaw was found in the redirect_uri validation logic in Keycloak
CVE-2023-6134 MEDIUM 4.6 UPGRADE UPGRADE A flaw was found in Keycloak that prevents certain schemes in redirects, but permits them if a wildcard is app
CVE-2025-8419 MEDIUM 5.3 MITIGATE A vulnerability was found in Keycloak-services

References

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