CVE-2026-49975Public exploitNetwork attack vectorHinoki check available

Remote service interruption via uncounted Cookie headers

Published Jun 8, 2026 · Updated Jun 8, 2026

Denial of service in Apache HTTP Server 2.4.17 through 2.4.67 allows remote attackers to exhaust memory via HTTP/2 requests. The mod_http2 request-header path merges repeated Cookie fields without counting each merge against LimitRequestFields, repeatedly allocating memory. HTTP/2 must be enabled and reachable; held-open streams retain the allocations and interrupt normal request processing.

CVSS severity7.5
High
EPSS probability34.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Denial of service in Apache HTTP Server 2.4.17 through 2.4.67 allows remote attackers to exhaust memory via HTTP/2 requests. The mod_http2 request-header path merges repeated Cookie fields without counting each merge against LimitRequestFields, repeatedly allocating memory. HTTP/2 must be enabled and reachable; held-open streams retain the allocations and interrupt normal request processing.

The record

CVE
CVE-2026-49975
Published
Jun 8, 2026
Updated
Jun 8, 2026
Vendor
The Apache Software Foundation
Product
Apache HTTP Server
Classifications
CWE-789, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.4.17 <=2.4.67

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache HTTP Serverversion=2.4.17 <=2.4.67

Published CVSS scores

7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-789Memory Allocation with Excessive Size Value
T1499.004Application or System Exploitation

Public exploit references

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Technologies

Your stack

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Your stack

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