CVE-2021-32791

Name: CVE-2021-32791
Creator: NVD / NIST
Published: 2021-07-26T17:15:08.1+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.9/10EPSS 1.50%

Last modified Jun 17, 2026

CVE-2021-32791 is a medium-severity vulnerability rated 5.9/10 on the CVSS scale. 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. EPSS estimates a 1.50% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

5.9/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS Probability

1.50%

71.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Openidc	Mod Auth Openidc	< 2.4.9
Fedoraproject	Fedora	33
Fedoraproject	Fedora	34

References

https://github.com/zmartzone/mod_auth_openidc/commit/375407c16c61a70b56fdbe13b0d2c8f11398e92cPatch, Third Party Advisory
https://github.com/zmartzone/mod_auth_openidc/releases/tag/v2.4.9Release Notes, Third Party Advisory
https://github.com/zmartzone/mod_auth_openidc/security/advisories/GHSA-px3c-6x7j-3r9rPatch, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/04/msg00034.html
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FZVF6BSJLRQZ7PFFR4X5JSU6KUJYNOCU/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QXAWKPT5LXZSUTFSJ6IWSZC7RMYYQXQD/
https://www.oracle.com/security-alerts/cpuapr2022.htmlPatch, Third Party Advisory
https://github.com/zmartzone/mod_auth_openidc/commit/375407c16c61a70b56fdbe13b0d2c8f11398e92cPatch, Third Party Advisory
https://github.com/zmartzone/mod_auth_openidc/releases/tag/v2.4.9Release Notes, Third Party Advisory
https://github.com/zmartzone/mod_auth_openidc/security/advisories/GHSA-px3c-6x7j-3r9rPatch, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/04/msg00034.html
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FZVF6BSJLRQZ7PFFR4X5JSU6KUJYNOCU/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QXAWKPT5LXZSUTFSJ6IWSZC7RMYYQXQD/
https://www.oracle.com/security-alerts/cpuapr2022.htmlPatch, Third Party Advisory

Timeline

Published: Jul 26, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-32791?

How severe is CVE-2021-32791?

CVE-2021-32791 has a CVSS score of 5.9/10 (MEDIUM severity). The EPSS model estimates a 1.50% probability of exploitation in the next 30 days.

How do I fix CVE-2021-32791?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-32791?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST