CVE-2026-23918

HIGH LAB

Apache HTTP Server: http2: double free and possible RCE on early reset

Title source: cna
STIX 2.1

Exploitation Summary

EIP tracks 16 public exploits for CVE-2026-23918. PoCs published by alisunbul, striga-ai, adminlove520.

AI-analyzed exploit summary This is a functional exploit for CVE-2026-23918, a double-free vulnerability in Apache HTTP Server 2.4.66's mod_http2. It triggers a race condition by rapidly sending HEADERS and RST_STREAM frames, causing a denial of service (DoS) via SIGSEGV.

Description

Double Free and possible RCE vulnerability in Apache HTTP Server with the HTTP/2 protocol. This issue affects Apache HTTP Server: 2.4.66. Users are recommended to upgrade to version 2.4.67, which fixes the issue.

Exploits (16)

exploitdb WORKING POC
by alisunbul · pythonwebappsmultiple
https://www.exploit-db.com/exploits/52577

This is a functional exploit for CVE-2026-23918, a double-free vulnerability in Apache HTTP Server 2.4.66's mod_http2. It triggers a race condition by rapidly sending HEADERS and RST_STREAM frames, causing a denial of service (DoS) via SIGSEGV.

Classification
Working Poc 95%
Attack Type
Dos
Complexity
Moderate
Reliability
Racy
Target: Apache HTTP Server 2.4.66 with mod_http2
No auth needed
Prerequisites: HTTP/2 support on target server · Python h2 library
devstral-2 · analyzed May 27, 2026 Full analysis →
nomisec WORKING POC 5 stars
by striga-ai · poc
https://github.com/striga-ai/CVE-2026-23918

This repository contains a functional exploit for CVE-2026-23918, a double-free vulnerability in Apache httpd mod_http2 leading to pre-authentication remote code execution. The exploit includes a Docker environment for testing, a helper script to extract memory addresses, and a Python-based PoC that triggers the vulnerability to achieve RCE.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Complex
Reliability
Racy
Target: Apache httpd 2.4.66 with mod_http2
No auth needed
Prerequisites: Docker · Python 3 · vulnerable Apache httpd instance
devstral-2 · analyzed May 12, 2026 Full analysis →
github WORKING POC 4 stars
by adminlove520 · pythonpoc
https://github.com/adminlove520/CVE-Poc_All_in_One/tree/main/2026/CVE-2026-23918

This repository contains functional exploit code for CVE-2026-23918, a double-free vulnerability in Apache HTTP Server 2.4.66's mod_http2 module. The PoC includes both a single-target DoS script and a mass-target tool that triggers the vulnerability by sending rapid RST_STREAM frames, leading to server crashes.

Classification
Working Poc 100%
Attack Type
Dos
Complexity
Moderate
Reliability
Reliable
Target: Apache HTTP Server 2.4.66 with mod_http2
No auth needed
Prerequisites: HTTP/2 support on target server · SSL/TLS enabled on target server
devstral-2 · analyzed May 26, 2026 Full analysis →
nomisec SCANNER 2 stars
by qassam-315 · poc
https://github.com/qassam-315/CVE-2026-23918-Elite-Auditor

The repository contains a Python-based scanner for detecting CVE-2026-23918, a memory corruption flaw in Apache HTTP Server 2.4.66. It performs HTTP/2 handshake checks, version fingerprinting, and risk scoring but does not include exploit code.

Classification
Scanner 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: Apache HTTP Server 2.4.66
No auth needed
Prerequisites: HTTP/2 support on target · network access to target
devstral-2 · analyzed May 05, 2026 Full analysis →
nomisec WORKING POC 1 stars
by xeloxa · poc
https://github.com/xeloxa/CVE-2026-23918-Apache-H2-PoC

This repository contains a functional Python-based proof-of-concept exploit for CVE-2026-23918, a double-free vulnerability in Apache HTTP Server 2.4.66's mod_http2 module. The exploit demonstrates a reliable DoS attack by triggering a race condition in stream cleanup, with additional detection modes for vulnerability scanning.

Classification
Working Poc 95%
Attack Type
Dos
Complexity
Moderate
Reliability
Reliable
Target: Apache HTTP Server 2.4.66 with mod_http2
No auth needed
Prerequisites: Python 3.9+ · h2 library · HTTP/2 support on target
devstral-2 · analyzed May 07, 2026 Full analysis →
github WORKING POC
by XZ1r0 · pythonpoc
https://github.com/XZ1r0/cve-2026-poc-collection/tree/main/web/CVE-2026-23918

This repository contains a functional exploit for CVE-2026-23918, a double-free vulnerability in Apache httpd mod_http2 leading to pre-authentication remote code execution. The exploit includes a Python-based PoC that leverages memory corruption to achieve RCE, along with a helper script to extract necessary memory addresses from the target process.

Classification
Working Poc 100%
Attack Type
Rce
Complexity
Complex
Reliability
Racy
Target: Apache httpd 2.4.66 with mod_http2 and multi-threaded MPM (event/worker)
No auth needed
Prerequisites: Docker for environment setup · Python 3 for running the exploit · Access to /proc/PID/mem for address extraction
devstral-2 · analyzed May 21, 2026 Full analysis →
nomisec SCANNER
by sibersan · poc
https://github.com/sibersan/apache_audit_cve-2026-23918

This repository provides defensive audit tools for detecting CVE-2026-23918 and related CVEs in Apache HTTP Server. It includes scripts for passive external scanning (banner grabbing and ALPN negotiation) and local host auditing to determine vulnerability status without exploiting the vulnerabilities.

Classification
Scanner 100%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: Apache HTTP Server 2.4.66
No auth needed
Prerequisites: Access to the target server's HTTP/HTTPS endpoints for passive scanning · Local or SSH access to the target host for local auditing
devstral-2 · analyzed May 16, 2026 Full analysis →
nomisec WORKING POC
by Bencodin · poc
https://github.com/Bencodin/CVE-2026-23918-poc

This repository contains a functional PoC for CVE-2026-23918, a double-free vulnerability in Apache HTTP Server 2.4.66 with mod_http2. The exploit sends HEADERS followed by RST_STREAM frames to trigger heap corruption, potentially leading to RCE.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: Apache HTTP Server 2.4.66 with mod_http2 + Event MPM
No auth needed
Prerequisites: Apache HTTP Server 2.4.66 · mod_http2 enabled · Event MPM · HTTP/2 support
devstral-2 · analyzed May 13, 2026 Full analysis →
nomisec WRITEUP
by insomnisec · poc
https://github.com/insomnisec/Detections-CVE-2026-23918

This repository provides a detailed technical analysis and detection guidance for CVE-2026-23918, a double-free vulnerability in Apache HTTP Server's mod_http2 module. It includes detection rules for Suricata, ModSecurity, auditd, and YARA, along with mitigation steps and exploit mechanics.

Classification
Writeup 100%
Attack Type
Rce | Dos
Complexity
Moderate
Reliability
Reliable
Target: Apache HTTP Server 2.4.66 with HTTP/2 enabled and multi-threaded MPM
No auth needed
Prerequisites: Apache HTTP Server 2.4.66 · mod_http2 enabled · multi-threaded MPM (worker/event) · HTTP/2 support
devstral-2 · analyzed May 08, 2026 Full analysis →
nomisec WORKING POC
by alt3kx · poc
https://github.com/alt3kx/CVE-2026-23918

This repository contains a functional Python script (`h2ghost.py`) that detects CVE-2026-23918, a double-free vulnerability in Apache mod_http2. The exploit sends a crafted HTTP/2 request with HEADERS and RST_STREAM frames to trigger the vulnerability, which can lead to DoS or potential RCE in specific environments.

Classification
Working Poc 95%
Attack Type
Dos
Complexity
Trivial
Reliability
Reliable
Target: Apache httpd mod_http2 < 2.0.37
No auth needed
Prerequisites: Network access to target Apache server · HTTP/2 support enabled on the server
devstral-2 · analyzed May 07, 2026 Full analysis →
nomisec WORKING POC
by CYFARE · poc
https://github.com/CYFARE/CVE-2026-23918-Apache-HTTP-Server-DoubleFree-PoC

This repository contains a functional Python exploit for CVE-2026-23918, which triggers a double-free vulnerability in Apache HTTP Server 2.4.66 via HTTP/2 HEADERS + immediate RST_STREAM. The PoC demonstrates the vulnerability by sending crafted HTTP/2 frames to induce a double-free condition.

Classification
Working Poc 95%
Attack Type
Dos
Complexity
Moderate
Reliability
Reliable
Target: Apache HTTP Server 2.4.66
No auth needed
Prerequisites: HTTP/2 support on target server · TLS/SSL connection to target
devstral-2 · analyzed May 07, 2026 Full analysis →
nomisec SCANNER
by hackervlogofficial · poc
https://github.com/hackervlogofficial/CVE-2026-23918

This repository contains a Python-based scanner for detecting CVE-2026-23918, a double-free vulnerability in Apache HTTP/2. The tool checks for vulnerable Apache versions, HTTP/2 support, and MPM type without attempting exploitation.

Classification
Scanner 100%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: Apache HTTP Server 2.4.66
No auth needed
Prerequisites: network access to target server · SSL/TLS support on target
devstral-2 · analyzed May 07, 2026 Full analysis →
nomisec WRITEUP
by rshosting · poc
https://github.com/rshosting/Apache-CVE-2026-23918-fix

This repository provides a script to patch CVE-2026-23918, a double-free vulnerability in Apache HTTP Server 2.4.66 that could lead to RCE. The script automates system updates and service restarts but does not include exploit code.

Classification
Writeup 90%
Attack Type
Rce
Complexity
Moderate
Reliability
Theoretical
Target: Apache HTTP Server 2.4.66
Auth required
Prerequisites: root access · DNF package manager · cPanel/LiteSpeed environment
devstral-2 · analyzed May 06, 2026 Full analysis →
nomisec WORKING POC
by 12lie20 · poc
https://github.com/12lie20/CVE-2026-23918-test

This repository contains a functional PoC for CVE-2026-23918, a double-free vulnerability in Apache HTTP Server 2.4.66's mod_http2. The exploit triggers a race condition via rapid RST_STREAM frame sequencing, leading to a reliable DoS and potential RCE path.

Classification
Working Poc 95%
Attack Type
Dos
Complexity
Complex
Reliability
Reliable
Target: Apache HTTP Server 2.4.66 with mod_http2
No auth needed
Prerequisites: HTTP/2 enabled · Event MPM · Python with hpack and requests libraries
devstral-2 · analyzed May 05, 2026 Full analysis →

References (2)

Core 2
Core References

Scores

CVSS v3 8.8
EPSS 0.0676
EPSS Percentile 93.1%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact total

Details

CWE
CWE-415
Status published
Products (2)
apache/http_server 2.4.66
Apache Software Foundation/Apache HTTP Server 2.4.66
Published May 04, 2026
Tracked Since May 04, 2026