Home/CVE/mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions as an OpenID Co
CVE

CVE-2021-32785

mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions as an OpenID Co

mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. When mod_auth_openidc versions prior to 2.4.9 are configured to use an unencrypted Redis cache (OIDCCacheEncrypt off, OIDCSessionType server-cache, OIDCCacheType redis), mod_auth_openidc wrongly performed argument interpolation before passing Redis requests to hiredis, which would perform it again and lead to an uncontrolled format string bug. Initial assessment shows that this bug does not appear to allow gaining arbitrary code execution, but can reliably provoke a denial of service by repeatedly crashing the Apache workers.

This bug has been corrected in version 2.4.9 by performing argument interpolation only once, using the hiredis API. As a workaround, this vulnerability can be mitigated by setting OIDCCacheEncrypt to on, as cache keys are cryptographically hashed before use when this option is enabled.

MEDIUM · CVSS 5.3 EPSS 0.01593
Monitor
  • No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-134Use of Externally-Controlled Format String
CWE-134Use of Externally-Controlled Format String
▤

Affected Products & Versions

3
openidc mod auth openidc< 2.4.9
netapp cloud backupall versions
debian linuxall versions
▣

Scoring & Timeline

5.3
MEDIUM · CVSS v3.1 · security-advisories@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD22 Jul 2021 · 10:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
⚑

Vendor Advisories

8
suse-csafSUSE-SU-2025:4532-1
suse-csafopenSUSE-SU-2024:10624-1
msrcCVE-2021-32785
suse-csafSUSE-SU-2021:3352-1
suse-csafopenSUSE-SU-2021:1277-1
🔗

References & Sources

6
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/zmartzone/mod_auth_openidc/commit/dc672688dc1f2db7df8ad4abebc367116017a449PatchThird Party Advisory
https://github.com/zmartzone/mod_auth_openidc/releases/tag/v2.4.9Release NotesThird Party Advisory
https://github.com/zmartzone/mod_auth_openidc/security/advisories/GHSA-55r8-6w97-xxr4MitigationThird Party Advisory
https://lists.debian.org/debian-lts-announce/2023/04/msg00034.htmlMailing ListThird Party Advisory
https://security.netapp.com/advisory/ntap-20210902-0001/Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.htmlPatchThird Party Advisory
Intelligence Graph · click any node to traverse
CVETechnique ActorTool Family
drag to reposition · click any node to traverse · button top-right enlarges
External lookups - second-class, for what we don’t hold ourselves
NVDCVE.orgCISAVulnersExploit-DBGitHub PoCVulnCheck KEVGreyNoise
Vulnerabilities
CISA KEV catalog
CWE weaknesses
CAPEC attack patterns
Package vulnerabilities
Threat intelligence
Threat actors
Tools & malware
ATT&CK techniques
IOCs
Detection & defense
Sigma rules
YARA rules
Atomic Red Team tests
D3FEND countermeasures
Compliance
NIST 800-53
ISO 27001:2022
SOC 2 TSC
PCI-DSS v4.0
CIS Controls v8.1
About
All capabilities
Live statistics
Data sources
Privacy policy
Terms of service
threatengine.sh  ·  Open-source threat intelligence platform  ·  100+ authoritative sources  ·  Every fact traces to its origin