#VU16019 Null pointer dereference in PHP - CVE-2018-19396

Vulnerability identifier: #VU16019

Vulnerability risk: Low

CVSSv4.0: 7.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2018-19396

CWE-ID: CWE-476

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
PHP
Universal components / Libraries / Scripting languages

Vendor: PHP Group

Description

The vulnerability allows a remote attacker to cause DoS condition on the target system.

The vulnerability exists due to NULL pointer dereference condition that exists in the ext/standard/var_unserializer.c file when an unserialize call is made for the com, dotnet, or variant class. A remote attacker can send a specially crafted request that submits malicious input, trigger a NULL pointer dereference condition and cause the software to crash.

Mitigation
Install update from vendor's website.

Vulnerable software versions

PHP: 7.1.0 - 7.1.24

---

External links
https://bugs.php.net/bug.php?id=77177

---

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.