CVE-2026-49975: CVE-2026-49975: Memory Allocation with Excessive Size Value vulnerability in Apache HTTP Server's mod_http…

What it is

Memory Allocation with Excessive Size Value vulnerability in Apache HTTP Server's mod_http leads to denial of service via malicious HTTP requests. This issue affects Apache HTTP Server: from 2.4.17 through 2.4.67.

Exploitation evidence

First exploit evidence seen: 2026-06-08 (earliest date across the sources below).

Exploited in the wild

No source on this site lists in-the-wild exploitation yet (CISA KEV, VulnCheck KEV).

Public exploit code

GitHub proof-of-concept repositories

14 public repositories from 14 accounts, first seen 2026-06-08. Most starred: mrx-arafat/CVE-2026-49975-POC (29 stars), view repository.

Verify before running: public PoCs can be malicious. Read the code and only run it in an isolated lab. A PoC means exploit code is public, not that this CVE is exploited in the wild.

Sources: nomi-sec/PoC-in-GitHub.

How to fix it

Fixed versions

• apache http server: upgrade to 2.4.68 or later (affected from 2.4.17)

Derived from the NVD CPE configuration (versionEndExcluding / versionEndIncluding). Always confirm with the vendor advisory.

Vendor advisories and patches

• https://httpd.apache.org/security/vulnerabilities_24.html (Vendor Advisory)

MITRE ATT&CK mitigations for this chain

• M1037 Filter Network Traffic (for T1499) : Leverage services provided by Content Delivery Networks (CDN) or providers specializing in DoS mitigations to filter traffic upstream from services. Filter boundary traffic by blocking source addresses sourcing the attack, blocking ports that are being targeted, or blocking protocols being used for transport. To defend

Detection Generic guidance

• Impact: Monitor service availability, unexpected encryption activity and mass file changes.

Response checklist Generic guidance

1. Inventory: find every instance of the affected product and version (include internet-facing and forgotten ones).
2. Patch or mitigate per the vendor advisory; if you cannot patch, remove internet exposure or apply the vendor workaround.
3. Assume compromise if the system was exposed before patching: hunt for the indicators in the advisory and review logs back to the disclosure date.
4. Rotate credentials and secrets stored on or used by the affected system if compromise cannot be ruled out.