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CVE-2021-32791

Hardcoded static IV and AAD with a reused key in AES GCM encryption in mod_auth_openidc

MEDIUM
5.9
CVSS Score
Published: July 26, 2021 at 12:00 AM UTC
Updated: June 17, 2026 at 03:53 AM UTC
3 products affected across 3 vendorsFedoraMod Auth OpenidcMod Auth Openidc· also runs on 1 platform

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Severity
MEDIUM5.9
Exploit prediction
EPSS 2%

Description

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. In mod_auth_openidc before version 2.4.9, the AES GCM encryption in mod_auth_openidc uses a static IV and AAD. It is important to fix because this creates a static nonce and since aes-gcm is a stream cipher, this can lead to known cryptographic issues, since the same key is being reused. From 2.4.9 onwards this has been patched to use dynamic values through usage of cjose AES encryption routines.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Fedora· Fedora Projectrpm
95%
3334
Mod Auth Openidc· Openidc
95%
v < 2.4.9
Affected range stops below 2.4.9, so it looks safe — our inference, not a vendor statement
apache-http-server (environment)
Mod Auth Openidc· Zmartzone
60%
v < 2.4.9
Affected range stops below 2.4.9, so it looks safe — our inference, not a vendor statement

Runs on — not affected

The affected product only carries this flaw when running on these platforms. The platforms themselves are not vulnerable.

References (7)

PatchThird Party Advisory
Source: [email protected]
https://github.com/zmartzone/mod_auth_openidc/commit/375407c16c61a70b56fdbe13b0d2c8f11398e92c
Release NotesThird Party Advisory
Source: [email protected]
https://github.com/zmartzone/mod_auth_openidc/releases/tag/v2.4.9
PatchThird Party Advisory
Source: [email protected]
https://github.com/zmartzone/mod_auth_openidc/security/advisories/GHSA-px3c-6x7j-3r9r
Mailing List
Source: [email protected]
https://lists.debian.org/debian-lts-announce/2023/04/msg00034.html
Vendor Advisory
Source: [email protected]
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FZVF6BSJLRQZ7PFFR4X5JSU6KUJYNOCU/
Vendor Advisory
Source: [email protected]
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QXAWKPT5LXZSUTFSJ6IWSZC7RMYYQXQD/
x_refsource_MISCPatchThird Party Advisory
Source: [email protected]
https://www.oracle.com/security-alerts/cpuapr2022.html

CVSS

5.9MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-323CWE-330

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