CVE-2026-57941Network attack vectorHinoki check available

Memory corruption via reentrant HTTP/2 scratch buffer

Published Oct 1, 2026 · Updated Oct 1, 2026

Use-after-free in Apache HTTP Server 2.4.0 through 2.4.68 allows remote attackers to corrupt server memory through HTTP/2 traffic. In mod_http2, reentrant processing reuses the shared session->bbtmp buffer; Apache identifies this as the use-after-free and wild-write path but does not publish the exact trigger sequence. Exposure requires mod_http2 and HTTP/2 to be enabled, and the published record does not establish code execution.

CVSS severityUnavailable
Unscored
EPSS probability0.60%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Use-after-free in Apache HTTP Server 2.4.0 through 2.4.68 allows remote attackers to corrupt server memory through HTTP/2 traffic. In mod_http2, reentrant processing reuses the shared session->bbtmp buffer; Apache identifies this as the use-after-free and wild-write path but does not publish the exact trigger sequence. Exposure requires mod_http2 and HTTP/2 to be enabled, and the published record does not establish code execution.

The record

CVE
CVE-2026-57941
Published
Oct 1, 2026
Updated
Oct 1, 2026
Vendor
The Apache Software Foundation
Product
Apache HTTP Server
Classifications
CWE-416, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 1, 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?

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  1. Affected versionversion=2.4.0 <=2.4.68

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache HTTP Serverversion=2.4.0 <=2.4.68

Published CVSS scores

No CVSS assessment is available in this record.

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.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

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