CVE-2024-2757Public exploitNetwork attack vector

Application hang via crafted MIME-header text

Published Apr 29, 2024 · Updated Nov 4, 2025

Denial of service in PHP 8.3.0 through 8.3.4 allows remote attackers to hang applications through crafted MIME-header text. The mb_encode_mimeheader function enters a non-returning loop on long non-space text followed by a space; the faulty internal operation is undisclosed. Exposure requires an application to pass attacker-controlled text to this function, causing the associated PHP process to remain stuck rather than return.

CVSS severity7.5
High
EPSS probability1.92%
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 PHP 8.3.0 through 8.3.4 allows remote attackers to hang applications through crafted MIME-header text. The mb_encode_mimeheader function enters a non-returning loop on long non-space text followed by a space; the faulty internal operation is undisclosed. Exposure requires an application to pass attacker-controlled text to this function, causing the associated PHP process to remain stuck rather than return.

The record

CVE
CVE-2024-2757
Published
Apr 29, 2024
Updated
Nov 4, 2025
Vendor
The PHP Group
Product
PHP
Classifications
CWE-400, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 29, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 2025Record 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=8.3
  2. Affected versionversion=8.3.* <8.3.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The PHP Group · PHPversion=8.3; version=8.3.* <8.3.5

Published CVSS scores

7.5PHP php-src GitHub Security AdvisoryCVSS: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-400Uncontrolled Resource Consumption
T1499.004Application or System Exploitation

Public exploit references

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

Technologies

Your stack

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Your stack

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