OpenIDC mod_auth_openidc 2.4.15.2/2.4.16.11 State-Cookie Parser out-of-bounds write

CVSS Meta Temp Score
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CTI Interest Score
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6.3$0-$5k0.44

Summaryinfo

A vulnerability described as problematic has been identified in OpenIDC mod_auth_openidc. Affected is an unknown function of the component State-Cookie Parser. The manipulation results in out-of-bounds write. This vulnerability is known as CVE-2026-54789. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability, which was classified as problematic, was found in OpenIDC mod_auth_openidc. Affected is an unknown code block of the component State-Cookie Parser. The manipulation with an unknown input leads to a out-of-bounds write vulnerability. CWE is classifying the issue as CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. This is going to have an impact on availability. CVE summarizes:

mod_auth_openidc is an OpenID Certified authentication and authorization module for the Apache 2.x HTTP server that implements the OpenID Connect Relying Party functionality. Prior to 2.4.19.4, an out-of-bounds read and a one-byte out-of-bounds write exist in the state-cookie parser of `mod_auth_openidc`. The issue is fixed in version 2.4.19.4 by stopping the scan at the string terminator so a value-less token is rejected. No in-product workarounds are available. As a stop-gap, an upstream reverse proxy or WAF that rejects or normalizes malformed `Cookie` headers (tokens lacking `=`) can reduce exposure, but upgrading is the recommended remediation.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-54789 since 06/16/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are neither technical details nor an exploit publicly available.

Upgrading to version 2.4.19.4 eliminates this vulnerability.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.3

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.5
CNA Vector (GitHub_M): 🔒

CVSSv2info

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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Out-of-bounds write
CWE: CWE-787 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: mod_auth_openidc 2.4.19.4

Timelineinfo

06/16/2026 CVE reserved
08/21/2026 +66 days Advisory disclosed
08/21/2026 +0 days VulDB entry created
08/21/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-54789 (🔒)
GCVE (CVE): GCVE-0-2026-54789
GCVE (VulDB): GCVE-100-394140

Entryinfo

Created: 08/21/2026 18:26
Changes: 08/21/2026 18:26 (64)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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