CVE-2026-23918
📛 CVE Title
Apache HTTP Server: http2: double free and possible RCE on early reset
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.
Overview
- State
- PUBLISHED
- Assigner (CNA)
- apache
- CVSS severity
- high
- CVSS score
- 8.8 / 10
- CVSS vector
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H- Effective score
- 8.8 / 10 HIGH source: CNA overview
- MSRC score
- 8.8 / 10 HIGH MS rating: Important
- CWE(s)
-
CWE-415 - Reserved
- 2026-01-19
- Published
- 2026-05-04 16:44 UTC
- Last updated
- 2026-05-05 05:56 UTC
- Source
- https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/23xxx/CVE-2026-23918.json
- Linked Threat
- CVE-2026-23918 — CVE-2026-23918
NVD triage scoring NVD CVE 2.0
Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.
- NVD published
- 2026-05-04 15:16:03 UTC
- NVD last modified
- 2026-05-04 20:24:58 UTC
- NVD CVSS v3.1
- 8.8 / 10 HIGH source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
- NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H- Exploitability subscore
- 2.8 / 10
- Impact subscore
- 5.9 / 10
- EPSS score
- 0.0005 (probability of exploitation in next 30 days)
- EPSS percentile
- 15.42% vs all CVEs — higher = more likely to be exploited, as of 2026-05-25
NVD / KEV / EPSS data refreshed 2026-05-25 19:04 UTC. Re-run the 🛰 Backfill from NVD button above to refresh.
European Union Vulnerability Database ENISA EUVD
ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.
- EUVD ID
-
EUVD-2026-26955 - Assigner
- apache
- Published
- May 4, 2026, 2:44:28 PM
- Updated
- May 5, 2026, 3:56:10 AM
- EUVD base score (CVSS 3.1)
-
8.8 / 10
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - EUVD-reported EPSS
- 0.9500
- Vendors
- Apache Software Foundation
- Products
-
Apache HTTP Server (2.4.66)
ENISA 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.
EUVD references (1)
Microsoft Security Response Center MSRC
Microsoft's vendor-authoritative record from the Security Update Guide — its own CVSS score, impact, severity rating, exploit assessment, and KB-article fixes. Refreshed 2026-08-15 03:01 UTC (source: CVRF).
- MS severity
- Important
- MS CVSS base score
- 8.8 / 10 (temporal 8.8)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Release
- 2026-May
Microsoft remediations / KB articles (2)
- CBL-Mariner Releases — Vendor Fix / Security Update (fixed build 2.4.67-1)
- https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade — None Available / CBL-Mariner Releases
Affected products (1)
| Vendor | Product | Versions | Platforms |
|---|---|---|---|
| Apache Software Foundation | Apache HTTP Server |
2.4.66 (affected)
|
— |
Affected products — CPE 2.3 (1) NVD
NVD's normalized CPE 2.3 matchers, used by vendor tools (vulnerability scanners, asset managers) for automated detection. Compare with the CNA's free-text "Affected products" section above.
cpe:2.3:a:apache:http_server:2.4.66:*:*:*:*:*:*:*
Vendor references (1)
References embedded in the original CVE record by the assigning CNA.
- https://httpd.apache.org/security/vulnerabilities_24.html vendor-advisory
MITRE references (1) cveawg.mitre.org
Pulled from MITRE's CVE Services API by the 🛰 Backfill from MITRE button.
- https://httpd.apache.org/security/vulnerabilities_24.html vendor-advisory
Web references (14)
DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.
- None Available msrc
- MSRC update guide: CVE-2026-23918 msrc
- https://security.alpinelinux.org/vuln/CVE-2026-23918 rapid7:security.alpinelinux.org
- https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-26955 rapid7:euvd.enisa.europa.eu
- http://cwe.mitre.org/data/definitions/415.html rapid7:cwe.mitre.org
- https://attackerkb.com/topics/CVE-2026-23918 rapid7:attackerkb.com
- https://www.first.org/epss/ tenable:www.first.org
- https://www.helpnetsecurity.com/2026/05/18/debian-13-5-released/ tenable:www.helpnetsecurity.com
- https://www.securityweek.com/critical-high-severity-vulnerabilities-patched-in-apache-mina-http-server/ tenable:www.securityweek.com
- http://www.openwall.com/lists/oss-security/2026/05/04/19 tenable:www.openwall.com
- https://nvd.nist.gov/vuln/detail/CVE-2026-23918 tenable:nvd.nist.gov
- https://securityaffairs.com/191759/security/apache-fixes-critical-http-2-double-free-flaw-cve-2026-23918-enabling-rce.html tenable:securityaffairs.com
- https://thehackernews.com/2026/05/critical-apache-http2-flaw-cve-2026.html tenable:thehackernews.com
- https://www.cve.org/CVERecord?id=CVE-2026-23918 tenable:www.cve.org
NVD-tagged references (2)
Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.
- http://www.openwall.com/lists/oss-security/2026/05/04/19 af854a3a-2127-422b-91ae-364da2661108 Mailing ListThird Party Advisory
- https://httpd.apache.org/security/vulnerabilities_24.html security@apache.org Vendor Advisory
Remediations (15)
Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.
-
web:app.opencve.io
A double free in the HTTP/2 implementation of Apache HTTP Server can be triggered during an early reset, potentially allowing an attacker to execute arbitrary code on the server. The flaw involves both double‑free semantics described by CWE‑415 and the uncontrolled memory deallocation pattern of CWE‑1341, and can compromise confidentiality, integrity, and availability if exploited.
2026-05-23 21:15 UTC -
web:cybersecuritynews.com
Microsoft has released its April 2026 Patch Tuesday security update, addressing 168 vulnerabilities across its product portfolio including one actively exploited zero-day and one publicly disclosed flaw that organizations must prioritize immediately.
2026-05-23 21:15 UTC -
web:nvd.nist.gov
An official website of the United States government Here's how you know
2026-05-23 21:15 UTC -
web:portal.msrc.microsoft.com
The Security Update Guide provides information on the latest Microsoft security updates, helping users understand and address potential vulnerabilities effectively.
2026-05-23 21:15 UTC -
web:socprime.com
Explore Detections CVE-2026-23918 Mitigation The core fix is to upgrade Apache HTTP Server from 2.4.66 to 2.4.67. Apache's security advisory explicitly recommends moving to the patched version, and SecurityWeek notes that the release fixes 11 vulnerabilities, including this critical HTTP/2 issue.
2026-05-23 21:15 UTC -
web:thecybersecguru.com
Apache HTTP Server releases version 2.4.67 to fix a critical RCE vulnerability ( CVE-2026-23918 ) and privilege escalation flaws. Upgrade now
2026-05-23 21:15 UTC -
web:thehackernews.com
Apache fixes CVE-2026-23918 in HTTP/2; double-free flaw enables DoS and RCE, impacting version 2.4.66 users.
2026-05-23 21:15 UTC -
web:www.appsecmaster.net
Remediation & Hardening Checklist Immediate Action: Upgrade Apache The only complete fix for CVE-2026-23918 is to upgrade the Apache HTTP Server to version 2.4.67 or later. There is no configuration-level workaround that eliminates the vulnerability while preserving HTTP/2 functionality.
2026-05-23 21:15 UTC -
web:www.uvcyber.com
The combination of unauthenticated network access, trivial DoS, and a viable RCE chain against common deployment defaults makes CVE-2026-23918 one of the more consequential Apache vulnerabilities in recent years. Organizations that delay remediation accept material risk of service disruption and potential compromise of web-tier infrastructure.
2026-05-23 21:15 UTC -
web:zecurit.com
Get the complete breakdown of Microsoft's May 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .
2026-05-23 21:15 UTC -
web:hacklido.com
For the Hacklido community, we recommend an immediate " Patch and Verify" posture. Strategic Defensive Steps: Immediate Update: Administrators must prioritize updating to the latest patched version of Apache HTTP Server (v2.4.67 or higher) which includes the fix for CVE-2026-23918 .
2026-05-26 02:46 UTC -
web:hadrian.io
Technical analysis of CVE-2026-23918 in Apache HTTP Server 2.4.66. Understand the double-free bug, exploitation path, and remediation guidance.
2026-05-26 02:46 UTC -
web:security.berkeley.edu
SUMMARY A critical double-free vulnerability in Apache HTTP Server's HTTP/2 module is vulnerable to unauthenticated Remote Code Execution (RCE) and Denial of Service (DoS) attacks. [1] IMPACT Attackers can potentially execute arbitrary code remotely by exploiting this vulnerability or conduct Denial of Service attacks by continually crashing Apache worker processes. . WHAT IS VULNERABLE Debian ...
2026-05-26 02:46 UTC -
web:securityboulevard.com
CVE-2026-23918 Mitigation & Remediation Organizations running Apache HTTP Server 2.4.66 should upgrade to version 2.4.67 immediately. The update removes the vulnerable HTTP/2 code path and addresses additional security vulnerabilities fixed in the same release.
2026-05-26 02:46 UTC -
web:ubuntu.com
Ubuntu is an open source software operating system that runs from the desktop, to the cloud, to all your internet connected things.
2026-05-26 02:46 UTC
AI Forensic Analysis
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Raw JSON
The full cvelistV5 record. Download as CVE-2026-23918.json.
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