CVE-2015-6835

PHP Session Deserializer - Use-After-Free

Severity Score

9.8

*CVSS v3

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

The session deserializer in PHP before 5.4.45, 5.5.x before 5.5.29, and 5.6.x before 5.6.13 mishandles multiple php_var_unserialize calls, which allow remote attackers to execute arbitrary code or cause a denial of service (use-after-free) via crafted session content.

La sesión deserializer en PHP en versiones anteriores a 5.4.45, 5.5.x en versiones anteriores a 5.5.29 y 5.6.x en versiones anteriores a 5.6.13 no es correctamente manejada en llamadas multiples php_var_unserialize, lo que permite a atacantes remotos ejecutar código arbitrario o causar una denegación del servicio (uso después de liberación de memoria) a través de una sesión de contenido manipulada.

A flaw was discovered in the way PHP performed object unserialization. Specially crafted input processed by the unserialize() function could cause a PHP application to crash or, possibly, execute arbitrary code.

PHP is an HTML-embedded scripting language commonly used with the Apache HTTP Server. Multiple flaws were discovered in the way PHP performed object unserialization. Specially crafted input processed by the unserialize() function could cause a PHP application to crash or, possibly, execute arbitrary code. Multiple flaws were found in the way the way PHP's Phar extension parsed Phar archives. A specially crafted archive could cause PHP to crash or, possibly, execute arbitrary code when opened.

*Credits: N/A

CVSS Scores

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Network

Attack Complexity

Low

Authentication

None

Confidentiality

Partial

Integrity

Partial

Availability

Partial

Attack Vector

Network

Attack Complexity

High

Authentication

None

Confidentiality

Partial

Integrity

Partial

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2015-09-08 CVE Reserved
2015-09-09 First Exploit
2015-09-15 CVE Published
2024-08-06 CVE Updated
2025-04-16 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date

CWE

CWE-416: Use After Free

CAPEC

References (10)

URL	Tag	Source
http://php.net/ChangeLog-5.php	X_refsource_confirm
http://www.securityfocus.com/bid/76734	Vdb Entry
http://www.securitytracker.com/id/1033548	Vdb Entry
https://bugs.php.net/bug.php?id=70219	X_refsource_confirm

URL	Date	SRC
https://www.exploit-db.com/exploits/38123	2015-09-09
https://github.com/ockeghem/CVE-2015-6835-checker	2017-07-24

URL	Date	SRC

URL	Date	SRC
http://www.debian.org/security/2015/dsa-3358	2023-11-07
https://security.gentoo.org/glsa/201606-10	2023-11-07
https://access.redhat.com/security/cve/CVE-2015-6835	2016-03-15
https://bugzilla.redhat.com/show_bug.cgi?id=1260647	2016-03-15

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.6.0 Search vendor "Php" for product "Php" and version "5.6.0"		alpha1		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.6.0 Search vendor "Php" for product "Php" and version "5.6.0"		alpha2		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.6.0 Search vendor "Php" for product "Php" and version "5.6.0"		alpha3		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.6.0 Search vendor "Php" for product "Php" and version "5.6.0"		alpha4		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.6.0 Search vendor "Php" for product "Php" and version "5.6.0"		alpha5		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.6.0 Search vendor "Php" for product "Php" and version "5.6.0"		beta1		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.6.0 Search vendor "Php" for product "Php" and version "5.6.0"		beta2		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.6.0 Search vendor "Php" for product "Php" and version "5.6.0"		beta3		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.6.0 Search vendor "Php" for product "Php" and version "5.6.0"		beta4		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.6.1 Search vendor "Php" for product "Php" and version "5.6.1"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.6.2 Search vendor "Php" for product "Php" and version "5.6.2"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.6.3 Search vendor "Php" for product "Php" and version "5.6.3"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.6.4 Search vendor "Php" for product "Php" and version "5.6.4"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.6.5 Search vendor "Php" for product "Php" and version "5.6.5"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.6.6 Search vendor "Php" for product "Php" and version "5.6.6"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.6.7 Search vendor "Php" for product "Php" and version "5.6.7"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.6.8 Search vendor "Php" for product "Php" and version "5.6.8"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.6.9 Search vendor "Php" for product "Php" and version "5.6.9"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.6.10 Search vendor "Php" for product "Php" and version "5.6.10"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.6.11 Search vendor "Php" for product "Php" and version "5.6.11"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.6.12 Search vendor "Php" for product "Php" and version "5.6.12"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				<= 5.4.44 Search vendor "Php" for product "Php" and version " <= 5.4.44"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.0 Search vendor "Php" for product "Php" and version "5.5.0"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.0 Search vendor "Php" for product "Php" and version "5.5.0"		alpha1		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.0 Search vendor "Php" for product "Php" and version "5.5.0"		alpha2		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.0 Search vendor "Php" for product "Php" and version "5.5.0"		alpha3		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.0 Search vendor "Php" for product "Php" and version "5.5.0"		alpha4		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.0 Search vendor "Php" for product "Php" and version "5.5.0"		alpha5		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.0 Search vendor "Php" for product "Php" and version "5.5.0"		alpha6		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.0 Search vendor "Php" for product "Php" and version "5.5.0"		beta1		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.0 Search vendor "Php" for product "Php" and version "5.5.0"		beta2		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.0 Search vendor "Php" for product "Php" and version "5.5.0"		beta3		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.0 Search vendor "Php" for product "Php" and version "5.5.0"		beta4		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.0 Search vendor "Php" for product "Php" and version "5.5.0"		rc1		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.0 Search vendor "Php" for product "Php" and version "5.5.0"		rc2		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.1 Search vendor "Php" for product "Php" and version "5.5.1"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.2 Search vendor "Php" for product "Php" and version "5.5.2"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.3 Search vendor "Php" for product "Php" and version "5.5.3"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.4 Search vendor "Php" for product "Php" and version "5.5.4"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.5 Search vendor "Php" for product "Php" and version "5.5.5"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.6 Search vendor "Php" for product "Php" and version "5.5.6"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.7 Search vendor "Php" for product "Php" and version "5.5.7"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.8 Search vendor "Php" for product "Php" and version "5.5.8"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.9 Search vendor "Php" for product "Php" and version "5.5.9"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.10 Search vendor "Php" for product "Php" and version "5.5.10"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.11 Search vendor "Php" for product "Php" and version "5.5.11"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.12 Search vendor "Php" for product "Php" and version "5.5.12"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.13 Search vendor "Php" for product "Php" and version "5.5.13"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.14 Search vendor "Php" for product "Php" and version "5.5.14"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.15 Search vendor "Php" for product "Php" and version "5.5.15"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.16 Search vendor "Php" for product "Php" and version "5.5.16"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.17 Search vendor "Php" for product "Php" and version "5.5.17"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.18 Search vendor "Php" for product "Php" and version "5.5.18"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.19 Search vendor "Php" for product "Php" and version "5.5.19"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.20 Search vendor "Php" for product "Php" and version "5.5.20"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.21 Search vendor "Php" for product "Php" and version "5.5.21"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.22 Search vendor "Php" for product "Php" and version "5.5.22"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.23 Search vendor "Php" for product "Php" and version "5.5.23"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.24 Search vendor "Php" for product "Php" and version "5.5.24"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.25 Search vendor "Php" for product "Php" and version "5.5.25"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.26 Search vendor "Php" for product "Php" and version "5.5.26"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.27 Search vendor "Php" for product "Php" and version "5.5.27"		-		Affected
Php Search vendor "Php"		Php Search vendor "Php" for product "Php"				5.5.28 Search vendor "Php" for product "Php" and version "5.5.28"		-		Affected