CVE-2023-45802Network attack vector

Memory exhaustion via HTTP/2 RST streams

Published Oct 23, 2023 · Updated Oct 14, 2024

Denial of service in Apache HTTP Server 2.4.17 through 2.4.57 allows remote attackers to exhaust memory via repeated HTTP/2 stream resets. The mod_http2 handling of client RST frames defers request-resource deallocation until connection close, allowing a busy connection to accumulate memory. Exploitation requires an HTTP/2 connection that remains open while sending repeated requests and resets; ordinary HTTP/2 traffic rarely triggers the condition, but the process can run out of memory before timeout or close.

CVSS severity5.9
Medium
EPSS probability3.02%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Apache HTTP Server 2.4.17 through 2.4.57 allows remote attackers to exhaust memory via repeated HTTP/2 stream resets. The mod_http2 handling of client RST frames defers request-resource deallocation until connection close, allowing a busy connection to accumulate memory. Exploitation requires an HTTP/2 connection that remains open while sending repeated requests and resets; ordinary HTTP/2 traffic rarely triggers the condition, but the process can run out of memory before timeout or close.

The record

CVE
CVE-2023-45802
Published
Oct 23, 2023
Updated
Oct 14, 2024
Vendor
The Apache Software Foundation
Product
Apache HTTP Server
Classifications
CWE-404, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 23, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 14, 2024Record 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 <=2.4.57

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache HTTP Serverversion=2.4.17 <=2.4.57

Published CVSS scores

5.9NVDCVSS:3.1/AV:N/AC:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-404Improper Resource Shutdown or Release
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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