CVE-2021-32785
published 2021-07-22CVE-2021-32785: mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions as an OpenID Connect Relying Party, authenticating…
PriorityP344high7.5CVSS 3.1
AVNACLPRNUINSUCNINAH
EPSS
2.73%
84.4th percentile
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.
Affected
7 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | debian_linux | — | — |
| debian | libapache2-mod-auth-openidc | < libapache2-mod-auth-openidc 2.4.9-1 (bookworm) | libapache2-mod-auth-openidc 2.4.9-1 (bookworm) |
| msrc | cbl2_httpd_2.4.52-1_on_cbl_mariner_2.0 | — | — |
| msrc | cbl_mariner_2.0_arm | — | — |
| msrc | cbl_mariner_2.0_x64 | — | — |
| openidc | mod_auth_openidc | < 2.4.9 | 2.4.9 |
| zmartzone | mod_auth_openidc | < 2.4.9 | 2.4.9 |
CVSS provenance
nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvdv2.04.3MEDIUMAV:N/AC:M/Au:N/C:N/I:N/A:P
osv7.5HIGH
vendor_msrc7.5HIGH
vendor_debian5.3MEDIUM
vendor_redhat5.3MEDIUM
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Red Hat
mod_auth_openidc: format string bug in the Redis cache implementation
vendor_redhat·2021-07-22·CVSS 5.3
CVE-2021-32785 [MEDIUM] CWE-134 mod_auth_openidc: format string bug in the Redis cache implementation
mod_auth_openidc: format string bug in the Redis cache implementation
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 Apach
Microsoft
Format string bug in the Redis cache implementation
vendor_msrc·2021-07-13·CVSS 7.5
CVE-2021-32785 [MEDIUM] CWE-134 Format string bug in the Redis cache implementation
Format string bug in the Redis cache implementation
FAQ: Is Azure Linux the only Microsoft product that includes this open-source library and is therefore potentially affected by this vulnerability?
One of the main benefits to our customers who choose to use the Azure Linux distro is the commitment to keep it up to date with the most recent and most secure versions of the open source libraries with which the distro is composed. Microsoft is committed to transparency in this work which is why we began publishing CSAF/VEX in October 2025. See this blog post for more information. If impact to additional products is identified, we will update the CVE to reflect this.
Mariner: Mariner
GitHub_M: GitHub_M
Customer Action Required: Yes
Remediation: CBL-Mariner Releases
Reference: https://lea
Debian
CVE-2021-32785: libapache2-mod-auth-openidc - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HT...
vendor_debian·2021·CVSS 5.3
CVE-2021-32785 [MEDIUM] CVE-2021-32785: libapache2-mod-auth-openidc - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HT...
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 a
OSV
CVE-2021-32785: mod_auth_openidc is an authentication/authorization module for the Apache 2
osv·2021-07-22·CVSS 7.5
CVE-2021-32785 [HIGH] CVE-2021-32785: mod_auth_openidc is an authentication/authorization module for the Apache 2
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 a
No detection rules found.
No public exploits indexed.
https://github.com/zmartzone/mod_auth_openidc/commit/dc672688dc1f2db7df8ad4abebc367116017a449https://github.com/zmartzone/mod_auth_openidc/releases/tag/v2.4.9https://github.com/zmartzone/mod_auth_openidc/security/advisories/GHSA-55r8-6w97-xxr4https://lists.debian.org/debian-lts-announce/2023/04/msg00034.htmlhttps://security.netapp.com/advisory/ntap-20210902-0001/https://www.oracle.com/security-alerts/cpuapr2022.htmlhttps://github.com/zmartzone/mod_auth_openidc/commit/dc672688dc1f2db7df8ad4abebc367116017a449https://github.com/zmartzone/mod_auth_openidc/releases/tag/v2.4.9https://github.com/zmartzone/mod_auth_openidc/security/advisories/GHSA-55r8-6w97-xxr4https://lists.debian.org/debian-lts-announce/2023/04/msg00034.htmlhttps://security.netapp.com/advisory/ntap-20210902-0001/https://www.oracle.com/security-alerts/cpuapr2022.html
2021-07-22
Published