CVE-2017-8923

CRITICAL

PHP < 7.4.24 - Out-of-bounds Write via zend_string_extend

Title source: llm
STIX 2.1

Description

The zend_string_extend function in Zend/zend_string.h in PHP through 7.1.5 does not prevent changes to string objects that result in a negative length, which allows remote attackers to cause a denial of service (application crash) or possibly have unspecified other impact by leveraging a script's use of .= with a long string.

References (3)

Core 3
Core References
Third Party Advisory, VDB Entry vdb-entry x_refsource_bid
http://www.securityfocus.com/bid/98518
Exploit, Issue Tracking, Vendor Advisory x_refsource_misc
https://bugs.php.net/bug.php?id=74577

Scores

CVSS v3 9.8
EPSS 0.0459
EPSS Percentile 89.4%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Details

CWE
CWE-787
Status published
Products (1)
php/php < 7.4.24
Published May 12, 2017
Tracked Since Feb 18, 2026