CVE-2026-33523
mediumpriority · track · 0EPSS 0.004 · 37 %ileDEEUJPNLRUUSEPSS · scored 2026-10-23
HTTP response splitting vulnerability in multiple Apache HTTP Server modules with untrusted or compromised backend servers. This issue affects Apache HTTP Server: from through 2.4.66. Users are recommended to upgrade to version 2.4.67, which fixes the issue.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (37)
Products and version ranges known to be affected.
- IBM Business Automation Workflow 24.0.0-24.0.1all versionscert_bundDEcpe:/a:ibm:business_automation_workflow:24.0.0_-_24.0.1
- IBM Business Automation Workflow 25.0.0-25.0.1all versionscert_bundDEcpe:/a:ibm:business_automation_workflow:25.0.0_-_25.0.1
- IBM DevOps Code ClearCase 11.0.0-11.0.0.05all versionscert_bundDEcpe:/a:ibm:devops_code_clearcase:11.0.0_-_11.0.0.05
- IBM Rational ClearCase 10.0.0-10.0.1.05all versionscert_bundDEcpe:/a:ibm:rational_clearcase:10.0.0_-_10.0.1.05
- IBM Rational ClearCase 9.1.0-9.1.0.10all versionscert_bundDEcpe:/a:ibm:rational_clearcase:9.1.0_-_9.1.0.10
- IBM Rational ClearQuest 10.0-10.0.10all versionscert_bundDEcpe:/a:ibm:rational_clearquest:10.0_-_10.0.10
- IBM Rational ClearQuest 9.1-9.1.0.11all versionscert_bundDEcpe:/a:ibm:rational_clearquest:9.1_-_9.1.0.11
advisories (4)
Vendor and ecosystem advisories describing this.
- NCSC-2026-0134Kwetsbaarheden verholpen in Apache HTTP ServerNL2026-05-06csaf · ncsc_nlNL
Apache Software Foundation heeft meerdere kwetsbaarheden verholpen in Apache HTTP Server.
- WID-SEC-W-2026-1354Apache HTTP Server: Mehrere SchwachstellenDeutsch2026-05-04csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Apache HTTP Server ausnutzen, um erweiterte Privilegien zu erlangen, beliebigen Code auszuführen, Sicherheitsmaßnahmen zu umgehen, vertrauliche Informationen offenzulegen oder einen Denial-of-Service-Zustand zu verursachen.
- BIT-apache-2026-33523Apache HTTP Server: multiple modules: HTTP response splitting forwarding malicious status line2026-05-05vendor · osvUS
HTTP response splitting vulnerability in multiple Apache HTTP Server modules with untrusted or compromised backend servers. This issue affects Apache HTTP Server: from through 2.4.66. Users are recommended to upgrade to version 2.4.67, which fixes the issue.
- JVNDB-2026-026853JVN iPedia advisory JVNDB-2026-0268532026-08-05vendor · jvndbJP
also known as (4)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (6)
External citations — patches, advisories, analysis.
- https://httpd.apache.org/security/vulnerabilities_24.htmlPatchcnnvd
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-33523cnnvd
- https://nvd.nist.gov/vuln/detail/CVE-2026-33523cnnvd
- https://httpd.apache.org/security/vulnerabilities_24.htmlenisa_euvd
- http://www.openwall.com/lists/oss-security/2026/05/04/23Mailing ListThird Party Advisorynvd
- https://httpd.apache.org/security/vulnerabilities_24.htmlVendor Advisorynvd
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