CVE-2026-119618: 
Apache HTTP Server Analyse et atténuation de la vulnérabilité

CVE-2026-119618 is a race condition vulnerability in Apache HTTP Server's mod_http2 module, specifically within the assign_headers() function, that can lead to heap corruption and remote code execution (RCE). It affects Apache HTTP Server versions 2.4.55 through 2.4.70, and mod_h2 (GitHub releases) versions 2.0.8 through 2.0.42. The vulnerability was disclosed on November 11, 2026, with patches released the same day. It carries a CVSS v3.1 base score of 9.8 (Critical), exploitable by unauthenticated remote attackers with no user interaction required (Apache Advisory, GitHub Advisory).

The root cause is a Concurrent Execution using Shared Resource with Improper Synchronization flaw (CWE-362), combined with Improper Input Validation (CWE-20), in the assign_headers() function of Apache's mod_http2 module. A timing window exists during HTTP/2 header assignment where a shared resource can be modified by a concurrently executing code sequence, leading to heap corruption. An unauthenticated remote attacker can trigger this condition by sending specially crafted HTTP/2 frames to a vulnerable server, requiring no privileges or user interaction. The attack vector is entirely network-based and low-complexity (Apache Advisory, Red Hat Bugzilla).

Successful exploitation allows an unauthenticated remote attacker to execute arbitrary code with the privileges of the httpd process, potentially resulting in full system compromise. Consequences include unauthorized modification of system configuration, exfiltration of sensitive data hosted on or accessible by the web server, and complete loss of service availability. The scope of impact extends to any backend systems or internal networks accessible from the compromised web server process, enabling lateral movement (Red Hat Bugzilla, Apache Advisory).

As of the disclosure date (November 11, 2026), there is no public proof-of-concept exploit and no confirmed evidence of in-the-wild exploitation. The EPSS score is reported as 0.0 at time of publication, and the vulnerability does not appear in the CISA KEV catalog based on available data. No threat actor attribution has been reported. Despite the absence of a public PoC, the critical CVSS score and unauthenticated network attack vector make this a high-priority patching target (Apache Advisory, GitHub Advisory).

1. Reconnaissance: Identify internet-facing Apache HTTP Server instances with HTTP/2 enabled (versions 2.4.55–2.4.70) using tools such as Shodan, Censys, or nmap with HTTP/2 detection scripts.
2. Confirm HTTP/2 support: Send an HTTP/2 upgrade or direct HTTP/2 connection request to confirm the target is running a vulnerable mod_http2 version.
3. Craft malicious HTTP/2 frames: Construct specially crafted HTTP/2 HEADERS frames designed to trigger a race condition in the assign_headers() function — exploiting the timing window during concurrent header processing.
4. Trigger the race condition: Send the crafted frames at high concurrency (e.g., multiple simultaneous HTTP/2 streams) to maximize the probability of hitting the vulnerable timing window, causing heap corruption in the server process.
5. Achieve code execution: If heap corruption is successfully triggered and controlled, leverage it to redirect execution flow and run arbitrary commands with the privileges of the httpd process (Red Hat Bugzilla, Apache Advisory).

• Network: Unusually high volumes of concurrent HTTP/2 connections or streams from a single source IP; malformed or oversized HTTP/2 HEADERS frames in network captures; unexpected outbound connections from the web server to external IPs.
• Logs: Apache error_log entries indicating segmentation faults, heap corruption, or abnormal mod_http2 errors; access logs showing repeated HTTP/2 requests with anomalous header structures from the same client.
• Process: Unexpected child processes spawned by the httpd parent process (e.g., /bin/sh, bash, curl, wget); crashes or restarts of the httpd process without clear cause.
• File System: New or modified files in web server directories, /tmp, or other writable locations created by the apache/www-data user; unexpected cron jobs or SSH keys added under the web server account (Red Hat Bugzilla).

The primary remediation is to upgrade Apache HTTP Server to a version beyond 2.4.70 (i.e., 2.4.71 or later), which includes the fix for this vulnerability. For deployments using the standalone mod_h2 module from GitHub, upgrade to a version beyond 2.0.42. As a temporary workaround, disabling mod_http2 (HTTP/2 support) eliminates the attack surface until patching is feasible. Red Hat has released multiple errata addressing this issue across RHEL 9 and RHEL 10 variants (RHSA-2026:98953, 98954, 98968, 98978, 98979, 98981, 98982) (Apache Advisory, Red Hat Bugzilla).

The vulnerability was quickly picked up by security news outlets and community trackers upon disclosure on November 11, 2026, with coverage from SecurityOnline, LinuxCompatible, and warp2search highlighting the critical RCE nature of the flaw. The Mastodon/InfoSec.exchange community flagged it as a high-priority patch. Red Hat responded rapidly with same-day errata across multiple RHEL product lines, reflecting the severity of the issue. No notable researcher deep-dive technical write-ups or vendor statements beyond the Apache advisory were available at time of reporting.