INSPECTING ARCHIVED INTELLIGENCE (OUTDATED VERSION).

Apache HTTP/2 Flaw CVE-2026-23918 Enables RCE

| 2026-05-06 11:00 HIGH MEDIUM
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Executive Summary AI-generated
The Apache HTTP Server, a widely used web server software, has been compromised with a critical vulnerability that could potentially lead to remote code execution. The issue is described as "double free and possible RCE" in the HTTP/2 protocol handling, which affects version 2.4.66 and has been addressed in version 2.4.67. Researchers have identified this flaw as CVE-2026-23918 with a CVSS score of 8.8, indicating its severity. The vulnerability is described by Bartlomiej Dmitruk from striga.ai and Stanislaw Strzalkowski from isec.pl, who discovered it while working on the Apache HTTP Server project. This issue has been addressed in subsequent updates to ensure the security of users relying on this software.
Technical Mitigations AI-generated
* Use secure memory allocation: Use a secure allocator like `apr_pool_create` with the `APR_MMAP_ALLOCATOR` flag to prevent memory corruption due to mmap reuse. * Implement a robust stream cleanup mechanism: Ensure that the Apache HTTP Server implementation has a reliable and efficient stream cleanup process, such as using a separate pool for each stream or implementing a more sophisticated garbage collection algorithm. * Use secure coding practices: Follow best practices for secure coding, including input validation, error handling, and memory management to prevent common vulnerabilities like double-free bugs. * Monitor system resources: Regularly monitor system resource utilization (e.g., CPU, memory) to detect potential issues before they become critical. This can help identify potential security exploits or performance bottlenecks early on. * Implement a secure HTTP/2 implementation: Ensure that the Apache HTTP Server implementation is designed with security in mind and has features like secure connection handling, authentication, and rate limiting to prevent common web application vulnerabilities.
Technical Observables
Intelligence Metadata
Actors / Malware / CVEs / Campaigns
CVE-2026-23918CVE-2026-23918
Target & Sectors
Global Scope
Incident Timeline
‎May 05, 2026
The Apache Software Foundation released security updates to address a critical HTTP/2 double-free flaw CVE-2026-23918.
tactic Remote Code Execution
 Ravie Lakshmanan  May 05, 2026 Vulnerability / Server Security The Apache Software Foundation (ASF) has released security updates to address several security vulnerabilities in the HTTP Server, including a severe vulnerability that could potentially lead to remote code execution (RCE).
tactic T1584.004 - Server
 Ravie Lakshmanan  May 05, 2026 Vulnerability / Server Security The Apache Software Foundation (ASF) has released security updates to address several security vulnerabilities in the HTTP Server, including a severe vulnerability that could potentially lead to remote code execution (RCE).
organisation The Apache
 Ravie Lakshmanan  May 05, 2026 Vulnerability / Server Security The Apache Software Foundation (ASF) has released security updates to address several security vulnerabilities in the HTTP Server, including a severe vulnerability that could potentially lead to remote code execution (RCE).
tactic T1592.002 - Software
 Ravie Lakshmanan  May 05, 2026 Vulnerability / Server Security The Apache Software Foundation (ASF) has released security updates to address several security vulnerabilities in the HTTP Server, including a severe vulnerability that could potentially lead to remote code execution (RCE).
organisation Vulnerability /
 Ravie Lakshmanan  May 05, 2026 Vulnerability / Server Security The Apache Software Foundation (ASF) has released security updates to address several security vulnerabilities in the HTTP Server, including a severe vulnerability that could potentially lead to remote code execution (RCE).
organisation ASF
 Ravie Lakshmanan  May 05, 2026 Vulnerability / Server Security The Apache Software Foundation (ASF) has released security updates to address several security vulnerabilities in the HTTP Server, including a severe vulnerability that could potentially lead to remote code execution (RCE).
‎2026/05/06
Apache fixes critical HTTP/2 double-free flaw CVE-2026-23918 enabling RCE.
infrastructure 8.8
Apache fixes critical HTTP/2 double-free flaw CVE-2026-23918 enabling RCE Apache fixed several flaws in HTTP Server, including CVE-2026-23918 (CVSS score of 8.8), a double-free bug in HTTP/2 that could allow remote code execution.
The Apache Software Foundation has released updates to fix multiple vulnerabilities in its HTTP Server, including CVE-2026-23918 (CVSS score of 8.8).
organisation The Apache
The Apache Software Foundation has released updates to fix multiple vulnerabilities in its HTTP Server, including CVE-2026-23918 (CVSS score of 8.8).
organisation CVE-2026
According to TheHackerNews , CVE-2026-23918 is a double-free flaw in Apache httpd 2.4.66’s mod_http2, triggered by a crafted HTTP/2 sequence that causes the same stream to be cleaned up twice, leading to memory corruption.
organisation Critical Apache
Critical Apache HTTP/2 Flaw (CVE-2026-23918)
organisation The Hacker News
When reached for comment, Dmitruk told The Hacker News via email that the severity of CVE-2026-23918 is critical, as it can be exploited to achieve denial-of-service (DoS) and RCE.
organisation DoS
When reached for comment, Dmitruk told The Hacker News via email that the severity of CVE-2026-23918 is critical, as it can be exploited to achieve denial-of-service (DoS) and RCE.
organisation APR
In certain setups, especially those using APR with mmap (common on Debian systems and official Docker images), it may also be exploited for remote code execution.
organisation x86_64
The second outcome is remote code execution, and we built a working proof of concept on x86_64.
infrastructure 2.4.66
This issue affects Apache HTTP Server 2.4.66 and has been addressed in version 2.4.67.
The vulnerability impacts version 2.4.66 and is resolved in version 2.4.67.
infrastructure 2.4.67
This issue affects Apache HTTP Server 2.4.66 and has been addressed in version 2.4.67.
The vulnerability impacts version 2.4.66 and is resolved in version 2.4.67.
organisation isec.pl
Researchers Bartlomiej Dmitruk, from striga.ai, and Stanislaw Strzalkowski from isec.pl discovered the vulnerability.
Striga.ai co-founder Bartlomiej Dmitruk and ISEC.pl researcher Stanislaw Strzalkowski have been credited with discovering and reporting the vulnerability.
organisation Striga.ai
Striga.ai co-founder Bartlomiej Dmitruk and ISEC.pl researcher Stanislaw Strzalkowski have been credited with discovering and reporting the vulnerability.
organisation MPM
Notably, MPM prefork is not affected, though the widespread use of HTTP/2 increases exposure.
The DoS, Dmitruk added, is trivial and works on any default deployment with mod_http2 and a multi-threaded MPM , whereas the RCE path requires an Apache Portable Runtime ( APR ) with the mmap allocator, which is the default on Debian-derived systems and on the official httpd Docker image.
organisation RCE
The DoS, Dmitruk added, is trivial and works on any default deployment with mod_http2 and a multi-threaded MPM , whereas the RCE path requires an Apache Portable Runtime ( APR ) with the mmap allocator, which is the default on Debian-derived systems and on the official httpd Docker image.
organisation Potential RCE
Enables DoS and Potential RCE.
organisation nghttp2
Two nghttp2 callbacks then fire in sequence, on_frame_recv_cb for the RST and on_stream_close_cb for the close, and both end up calling h2_mplx_c1_client_rst -> m_stream_cleanup, which pushes the same h2_stream pointer onto the spurge cleanup array twice.
organisation RST
Two nghttp2 callbacks then fire in sequence, on_frame_recv_cb for the RST and on_stream_close_cb for the close, and both end up calling h2_mplx_c1_client_rst -> m_stream_cleanup, which pushes the same h2_stream pointer onto the spurge cleanup array twice.
organisation Dmitruk
Dmitruk also pointed out that the MPM prefork is not affected by the flaw.
Tactical Metrics
Metrics
infrastructure
‎8.8
Software Version
Apache fixes critical HTTP/2 double-free flaw CVE-2026-23918 enabling RCE Apache fixed several flaws in HTTP Server, including CVE-2026-23918 (CVSS score of 8.8), a double-free bug in HTTP/2 that could allow remote code execution.
The Apache Software Foundation has released updates to fix multiple vulnerabilities in its HTTP Server, including CVE-2026-23918 (CVSS score of 8.8).
Metrics
infrastructure
‎2.4.66
Software Version
The vulnerability impacts version 2.4.66 and is resolved in version 2.4.67.
This issue affects Apache HTTP Server 2.4.66 and has been addressed in version 2.4.67.
Metrics
infrastructure
‎2.4.67
Software Version
The vulnerability impacts version 2.4.66 and is resolved in version 2.4.67.
This issue affects Apache HTTP Server 2.4.66 and has been addressed in version 2.4.67.
Intelligence Sources
The Hacker News 2026-05-05
Security Affairs 2026-05-06