---
title: "CVE-2016-5771\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2016-5771?format=md
keywords: index, follow
---

# CVE-2016-5771

Publication date 24 June 2016

Last updated 25 August 2025

---

Ubuntu priority

**Low**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**9.8 · Critical**

[Score breakdown](https://ubuntu.com/security/CVE-2016-5771?format=md#impact-score)

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## Description

spl\_array.c in the SPL extension in PHP before 5.5.37 and 5.6.x before
5.6.23 improperly interacts with the unserialize implementation and garbage
collection, which allows remote attackers to execute arbitrary code or
cause a denial of service (use-after-free and application crash) via
crafted serialized data.

[Read the notes from the security team](https://ubuntu.com/security/CVE-2016-5771?format=md#notes)

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| php5 | 16.04 LTS xenial | Not in release |
| 15.10 wily | Ignored end of life |
| 14.04 LTS trusty | Fixed 5.5.9+dfsg-1ubuntu4.19 |
| 12.04 LTS precise | Ignored |
| php7.0 | 16.04 LTS xenial | Not affected |
| 15.10 wily | Not in release |
| 14.04 LTS trusty | Not in release |
| 12.04 LTS precise | Not in release |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)
* [Patch details](https://ubuntu.com/security/CVE-2016-5771?format=md#patch-details)

## Notes

---

### [seth-arnold](https://launchpad.net/~seth-arnold)

Applications should never deserialize unauthenticated data.

---

### [mdeslaur](https://launchpad.net/~mdeslaur)

does not affect 7.0.x
precise needs backported fix
we will not be fixing this in Ubuntu 12.04 LTS. We recommend
validating untrusted data before unserializing.

### Patch details

For informational purposes only. We recommend not to cherry-pick updates. [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)

| Package | Patch details |
| --- | --- |
| php5 | * Upstream:   <http://git.php.net/?p=php-src.git;a=commit;h=3f627e580acfdaf0595ae3b115b8bec677f203ee> |

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

9.8 · Critical

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | Low |
  | Privileges required | None |
  | User interaction | None |
  | Scope | Unchanged |
  | Confidentiality impact | High |
  | Integrity impact | High |
  | Availability impact | High |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 9.8 · Critical |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-5771)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2016-5771)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2016-5771)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2016-5771)

### Related Ubuntu Security Notices (USN)

+ [USN-3045-1](https://usn.ubuntu.com/USN-3045-1)
+ PHP vulnerabilities
+ 2 August 2016

### Other references

* <https://www.cve.org/CVERecord?id=CVE-2016-5771>