# CVE-2016-10161: PHP out-of-bounds read in var_unserializer.c

Source: https://junglewise.ai/threats/cve-2016-10161-php-out-of-bounds-read-in-var-unserializer-c  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2017-01-24. Updated: 2026-05-13  
License: CC BY 4.0 with a link back

CVE-2016-10161 · Severity: high · CVSS 7.5 · Published 2017-01-24

PHP, a widely used web programming language, contains a vulnerability in how it processes certain types of data. An attacker can send specially crafted data to a web application to cause the server to crash, leading to a denial of service. This could disrupt business operations by making websites or web-based services unavailable to users.

Technologies: [PHP Group PHP](https://junglewise.ai/threats/technologies/php). Vendors: [PHP Group](https://junglewise.ai/threats/vendors/php-group).

## Quick answers

**Is CVE-2016-10161 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2016-10161 being exploited in the wild.

**How severe is CVE-2016-10161?** High severity, with a CVSS score of 7.5, published 24 January 2017.

**Which products and versions are affected?** PHP Group PHP before 5.6.30, 7.0.x before 7.0.15, 7.1.x before 7.1.1.

**Is there a fix for CVE-2016-10161?** A patch was published on 2017-01-19: Fixed in PHP 5.6.30 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2016-10161 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2016-10161?** Check whether you run PHP Group PHP at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A buffer over-read vulnerability exists in PHP's `object_common1` function within `ext/standard/var_unserializer.c`. The flaw is triggered during the deserialization process when handling nested data via the `finish_nested_data` call. A remote, unauthenticated attacker can exploit this by providing maliciously crafted serialized strings to an application that uses PHP's `unserialize()` function. Successful exploitation results in an application crash (Denial of Service) due to an out-of-bounds memory read. The issue was addressed in PHP versions 5.6.30, 7.0.15, and 7.1.1.

## Affected products

- PHP PHP before 5.6.30, 7.0.x before 7.0.15, 7.1.x before 7.1.1

## Timeline

- 2017-01-19: patched: Fixed in PHP 5.6.30
- 2017-01-24: disclosed: CVE published to NVD

## References

- [http://php.net/ChangeLog-5.php](http://php.net/ChangeLog-5.php)
- [http://php.net/ChangeLog-7.php](http://php.net/ChangeLog-7.php)
- [http://www.debian.org/security/2017/dsa-3783](http://www.debian.org/security/2017/dsa-3783)
- [http://www.securityfocus.com/bid/95768](http://www.securityfocus.com/bid/95768)
- [http://www.securitytracker.com/id/1037659](http://www.securitytracker.com/id/1037659)
- [https://access.redhat.com/errata/RHSA-2018:1296](https://access.redhat.com/errata/RHSA-2018:1296)
- [https://bugs.php.net/bug.php?id=73825](https://bugs.php.net/bug.php?id=73825)

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