CVE-2021-20202

Local data exposure and corruption via temporary-directory hijacking

Published May 12, 2021 · Updated Aug 3, 2024

Temporary-directory hijacking in Red Hat build of Keycloak before 13.0.0 allows local users to read or alter temporary data. Predictable directory names and unchecked mkdir or mkdirs failures let another account precreate directories with broad permissions before the Java process uses them. Exposure is limited to shared temporary directories on Unix-like systems other than macOS and can disclose exported data or corrupt caches.

CVSS severity7.3
High
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Temporary-directory hijacking in Red Hat build of Keycloak before 13.0.0 allows local users to read or alter temporary data. Predictable directory names and unchecked mkdir or mkdirs failures let another account precreate directories with broad permissions before the Java process uses them. Exposure is limited to shared temporary directories on Unix-like systems other than macOS and can disclose exported data or corrupt caches.

The record

CVE
CVE-2021-20202
Published
May 12, 2021
Updated
Aug 3, 2024
Vendor
Red Hat
Product
Red Hat build of Keycloak
Classifications
CWE-377, T1005
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 12, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=keycloak 13.0.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Red Hat · Red Hat build of Keycloakversion=keycloak 13.0.0

Published CVSS scores

7.3GitHub Advisory DatabaseCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L
6.3JLLeitschuh security-researchCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-377Insecure Temporary File
T1005Data from Local System

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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