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.

🗓️ 02 Oct 2025 06:11:00Reported by MicrosoftType

PHP up to 7.1.5 allows negative string length via concatenation, risking crash or denial of service.

Reporter	Title	Published	Views	Family All 119
BDU FSTEC	The vulnerability of the zend_string_extend function in the PHP interpreter allows a attacker to cause a service failure or exert other effects.	10 Aug 201700:00	–	bdu_fstec
CBLMariner	CVE-2017-8923 affecting package php 7.4.14-3	12 Jan 202509:15	–	cbl_mariner
Tenable Nessus	Rocky Linux 8 [CIQ] Security Update: apcu-panel / libzip / libzip-debuginfo / libzip-debugsource / etc Multiple Vulnerabilities (crlsa-2023_2903)	1 Oct 202600:00	–	nessus
Tenable Nessus	EulerOS 2.0 SP8 : php (EulerOS-SA-2022-2477)	9 Oct 202200:00	–	nessus
Tenable Nessus	EulerOS Virtualization 3.0.6.0 : php (EulerOS-SA-2023-2243)	13 Jun 202300:00	–	nessus
Tenable Nessus	openSUSE 15 Security Update : php7 (openSUSE-SU-2022:0699-1)	5 Mar 202200:00	–	nessus
Tenable Nessus	PHP 7.0.x < 7.0.19 Multiple Vulnerabilities	25 May 201700:00	–	nessus
Tenable Nessus	PHP 7.1.x < 7.1.5 Multiple Vulnerabilities	25 May 201700:00	–	nessus
Tenable Nessus	RHEL 8 : php:7.4 (RHSA-2023:2903)	16 May 202300:00	–	nessus
Tenable Nessus	RHEL 8 : php (Unpatched Vulnerability)	11 May 202400:00	–	nessus