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TL;DR
Apache released HTTP Server 2.4.71 on November 11 to fix CVE-2026-119618, a critical mod_http2 vulnerability that Apache says can lead to remote code execution. The reported affected versions are Apache HTTP Server 2.4.55–2.4.70 and standalone mod_h2 2.0.8–2.0.42; exposure requires HTTP/2 to be enabled. Exploitation in the wild was not confirmed in the cited checks, but Red Hat says public research demonstrated a reliable exploit.
The Apache HTTP Server project released version 2.4.71 on November 11 to fix CVE-2026-119618, a critical flaw in its mod_http2 module that Apache says can lead to remote code execution. The issue affects Apache HTTP Server versions 2.4.55 through 2.4.70 and specified standalone mod_h2 releases, but only servers with HTTP/2 enabled are exposed, according to Red Hat.
Apache describes the flaw as a concurrent-execution and synchronization vulnerability in the mod_http2 function assign_headers. The module handles HTTP/2 requests, which can be multiplexed so that multiple requests travel over one connection. Red Hat says a thread-safety defect could let one thread modify memory used by another, corrupting the server’s internal memory. Apache’s advisory says that condition can lead to remote code execution.
Red Hat assesses the vulnerability at CVSS 3.1 score 9.8 out of 10 and says a remote attacker able to reach an affected server could execute commands without authentication. That is Red Hat’s technical assessment; Apache’s advisory labels the issue critical. The National Vulnerability Database had not published its own score at the time described in the source material.
The upstream fix is Apache HTTP Server 2.4.71. Red Hat said it shipped fixed packages on November 11, including updates for RHEL 9 and 10. As of November 12, Debian’s stable bookworm and trixie releases were listed as vulnerable, while the fixed 2.4.71-1 package was available in unstable, sid. The source reported no published Ubuntu or SUSE advisory at that check. Administrators using distribution packages should follow the relevant vendor’s package advisory rather than assume that an upstream version number maps directly to their installed build.
Apache HTTP/2 CVE-2026-119618 What administrators should know
Apache says this critical mod_http2 flaw can lead to remote code execution. Exposure depends on HTTP/2 being enabled, and administrators should apply the upstream fix or their vendor’s fixed package.
Check versions and protocol
Reported affected versions are Apache HTTP Server 2.4.55–2.4.70 and standalone mod_h2 2.0.8–2.0.42.
- Affected version with h2 or h2c enabled
- Reachable services need prompt review
- Servers serving only HTTP/1.1
Why the flaw matters
A synchronization defect in mod_http2’s assign_headers function could let one thread corrupt memory used by another.
Remote code execution
Apache says the flaw can lead to remote code execution; Red Hat says a reachable server could allow unauthenticated command execution.
Reliable exploit reported
Red Hat says public research demonstrated a reliable exploit against a default-configured server with mod_http2 enabled.
What the reports establish
The available checks did not confirm attacks in the wild, but that does not establish that the flaw is safe from exploitation.
| Finding | Reported status |
|---|---|
| In-the-wild exploitation | Not confirmed in cited checks |
| Public exploit details | Not provided in the source material |
| Vendor coverage | Debian stable listed as vulnerable; Ubuntu and SUSE advisories not found at the time checked |
Patch and verify
Use the operating system vendor’s advisory where applicable, since package versions and backported fixes can differ from upstream.
Identify affected versions and check whether h2 or h2c is enabled.
Apply Apache 2.4.71 or the fixed package supplied by your vendor.
Verify the installed build and monitor vendor guidance for updated status.
HTTP/2 Settings Determine Exposure
The practical exposure question is whether HTTP/2 is enabled, not simply whether a server runs Apache. Red Hat says servers using HTTP/2 through the h2 or h2c protocols are affected, while servers serving only HTTP/1.1 are not. Apache documentation gives HTTP/1.1 as the default protocol setting, but configurations can enable HTTP/2; administrators should inspect their deployed configuration and service role rather than rely on defaults.
Wiz reported that 64% of cloud environments in its data had resources it considered vulnerable and that 51% had publicly exposed instances. Wiz cautioned that its figures did not account for configuration, so they are not a count of servers confirmed exploitable. The figures nonetheless indicate why teams should inventory externally reachable Apache systems and verify protocol settings before deciding which systems need immediate action.
Red Hat’s rating differs by product: it rates the issue critical overall but important for RHEL 9 and 10, saying separate allocators for HTTP/2 streams make exploitation more complex. This product-specific assessment does not remove the need to install the vendor’s correction. Red Hat listed RHEL 8 and earlier as not affected, while Red Hat JBoss Core Services and Red Hat Hardened Images remained listed as affected in the cited status.
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Reports Led to the November Patch
Apache credited Anthropic’s OSS Scanner and two researchers from Google Cloud Vulnerability Research with finding the issue. According to Apache, Anthropic reported it on October 26 and the Google Cloud researchers reported it on November 3. The CVE number was reserved on October 30, and Apache released the fix on November 11. That is a reported 16 days between the first report and the upstream release.
The separate reports matter as provenance for the security finding, but they do not establish how easy the flaw is to exploit or whether attacks are occurring. Apache’s advisory and Red Hat’s notices identify the affected software and remediation; Red Hat provides the more detailed public description of the memory-safety issue. The source material says Apache did not publish exploit details.
““Concurrent Execution using Shared Resource with Improper Synchronization vulnerability in Apache HTTP Server’s mod_http2 in assign_headers() can lead to RCE.””
— Apache HTTP Server project advisory
Exploit Activity Remains Unverified
The available reports do not confirm exploitation in the wild. Wiz said on November 11 it had seen no reports and that no exploit was available at publication. The CVE was not on the CISA Known Exploited Vulnerabilities catalog when checked on November 12, but the catalog version cited was released before the CVE became public, limiting what its absence can show.
At the same time, Red Hat said public research had demonstrated a reliable exploit against a default-configured server with mod_http2 enabled. The cited material does not name the researchers, provide their findings, or link to public exploit code. It is consequently unclear whether that research is publicly available in a form administrators can review, and the sources do not establish whether attackers have used it. Administrators should distinguish the absence of confirmed attacks from evidence that a flaw is not exploitable.
Vendor coverage was also incomplete at the time of reporting. The source found no published Ubuntu or SUSE advisory and said Debian’s stable branches remained vulnerable, while its unstable branch had the fixed package. Those status checks are time-specific and may have changed after November 12.
Patch and Recheck Vendor Notices
Administrators should identify Apache installations in the reported affected ranges, check whether h2 or h2c is enabled, and apply Apache 2.4.71 or the fixed package supplied by their operating-system vendor. Teams should verify the installed package after updating and consult vendor advisories for product-specific guidance, particularly where vendor builds use backported fixes or list separate product impact.
Organizations that cannot patch immediately should review whether HTTP/2 is enabled and whether affected services are reachable, then use their established change and risk procedures to reduce exposure while preparing an update. This is general defensive guidance, not a claim that disabling HTTP/2 is a substitute for installing the fix. Security teams should also monitor Apache, Linux distribution, and CISA notices for updated affected-version lists, package availability, and any confirmed exploitation reports.
The next meaningful developments are expected to come from vendor advisories and further technical disclosure. The sources available on November 12 did not provide a public exploit or confirmed in-the-wild attacks; either status could change, so administrators should treat the reported reliable-exploit research as a reason for prompt remediation.
Key Questions
Which Apache versions are affected by CVE-2026-119618?
Apache lists HTTP Server 2.4.55 through 2.4.70 and standalone mod_h2 versions 2.0.8 through 2.0.42 as affected. Apache HTTP Server 2.4.71 contains the upstream fix. Distribution packages may use vendor-specific versions or backports, so check the package advisory for your system.
Does the vulnerability affect every Apache server?
No. Red Hat says the issue affects servers with HTTP/2 enabled through h2 or h2c. Servers serving only HTTP/1.1 are not affected according to Red Hat. Administrators should inspect their actual configuration rather than assume HTTP/2 is off because of a default setting.
Has CVE-2026-119618 been exploited in attacks?
The cited sources did not confirm exploitation in the wild as of November 12, 2026. Wiz reported no known attacks, while Red Hat said public research had demonstrated a reliable exploit. The material does not establish that attackers have used it.
What should administrators do now?
Check affected Apache and mod_h2 installations, determine whether HTTP/2 is enabled, and install Apache 2.4.71 or the applicable vendor-fixed package. Follow current distribution advisories, since package status can change and vendor builds may differ from upstream releases.
Source: ThorstenMeyerAI.com
