CVE-2020-10758: A vulnerability was found in Keycloak before 11.0.1 where DoS attack is possible by sending twenty requests si

This month

HIGH 7.5REMOTEWATCHLISTUPGRADEDOWNGRADEDOWNGRADE

CVE-2020-10758 is a high-severity flaw (CVSS 7.5) affecting keycloak, openshift application runtimes, single sign-on. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A vulnerability was found in Keycloak before 11.0.1 where DoS attack is possible by sending twenty requests simultaneously to the specified keycloak server, all with a Content-Length header value that exceeds the actual byte count of the request body.

Why this priority

High severity
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.9% (top 20%)
CISA exploited list	No
Weakness	CWE-770
Published	2020-09-16
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

2020-09-16 16:15 UTCPublished CVE record published
2026-06-17 02:48 UTCUpdated Record last modified

redhat keycloak UPGRADE

Affected: < 11.0.1

Fixed in: 11.0.1

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 11.0.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade keycloak

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade keycloak

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

redhat openshift application runtimes DOWNGRADE

Affected: all versions · 1.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.0

1. Check installed version

apt-cache policy openshift-application-runtimes || rpm -q openshift-application-runtimes || openshift-application-runtimes --version

2. No fixed release: DOWNGRADE to a release before 1.0 (Debian / Ubuntu)

apt-cache madison openshift-application-runtimes sudo apt install openshift-application-runtimes=<VERSION_BEFORE_1.0> sudo apt-mark hold openshift-application-runtimes

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

dnf --showduplicates list openshift-application-runtimes sudo dnf downgrade openshift-application-runtimes-<VERSION_BEFORE_1.0> sudo dnf versionlock add openshift-application-runtimes

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.

redhat single sign-on DOWNGRADE

Affected: all versions · 7.0 · 7.4

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.0

1. Check installed version

apt-cache policy single-sign-on || rpm -q single-sign-on || single-sign-on --version

2. No fixed release: DOWNGRADE to a release before 7.0 (Debian / Ubuntu)

apt-cache madison single-sign-on sudo apt install single-sign-on=<VERSION_BEFORE_7.0> sudo apt-mark hold single-sign-on

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

dnf --showduplicates list single-sign-on sudo dnf downgrade single-sign-on-<VERSION_BEFORE_7.0> sudo dnf versionlock add single-sign-on

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-2020-10758?

keycloak: upgrade to 11.0.1; openshift application runtimes: downgrade or apply the listed mitigation; single sign-on: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-10758 being exploited?

CVE-2020-10758 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-2020-10758 affect?

CVE-2020-10758 affects keycloak, openshift application runtimes, single sign-on. Severity is high (CVSS 7.5). A vulnerability was found in Keycloak before 11.0.1 where DoS attack is possible by sending twenty requests simultaneously to the specified keycloak server, all with a Content-Length header value that exceeds the actual byte count of the re

How urgent is CVE-2020-10758?

Priority 56/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Keycloak vulnerabilities · Red Hat OpenShift vulnerabilities

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CVE-2023-6927 MEDIUM 4.6 MITIGATE DOWNGRADE A flaw was found in Keycloak
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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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