# CVE-2015-6834: Use after free in n/a

> Remote attackers can execute arbitrary code via use-after-free flaws in PHP's unserialization of Serializable, SplObjectStorage, and SplDoublyLinkedList.

- **Severity:** Critical 9.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 16 May 2016
- **Updated:** 6 Aug 2024
- **Also known as:** GHSA-6m7q-7r8q-jg24, UBUNTU-CVE-2015-6834

## What is CVE-2015-6834?

CVE-2015-6834 is a critical use after free vulnerability in Php Php, published on 16 May 2016. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Multiple use-after-free vulnerabilities in PHP before 5.4.45, 5.5.x before 5.5.29, and 5.6.x before 5.6.13 allow remote attackers to execute arbitrary code via vectors related to (1) the Serializable interface, (2) the SplObjectStorage class, and (3) the SplDoublyLinkedList class, which are mishandled during unserialization.

## Which versions are affected by CVE-2015-6834?

It affects 1 product.


Products: Php Php.

## How do I fix CVE-2015-6834?

Upgrade to a fixed version.

## Is CVE-2015-6834 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2015-6834 exists.

Public exploit code:

- PHP 5.4/5.5/5.6 - SplDoublyLinkedList 'Unserialize()' Use-After-Free (exploitdb)
- PHP 5.4/5.5/5.6 - SplObjectStorage 'Unserialize()' Use-After-Free (exploitdb)

## Other vulnerabilities in Php Php

- [CVE-2012-2688](https://insights.sbomify.com/CVE-2012-2688/): Integer overflow in n/a (critical 10.0)
- [CVE-2012-2376](https://insights.sbomify.com/CVE-2012-2376/): Memory corruption in n/a (critical 10.0)
- [CVE-2011-3268](https://insights.sbomify.com/CVE-2011-3268/): Memory corruption in n/a (critical 10.0)
- [CVE-2009-4143](https://insights.sbomify.com/CVE-2009-4143/): Other in n/a (critical 10.0)
- [CVE-2008-5557](https://insights.sbomify.com/CVE-2008-5557/): Memory corruption in n/a (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2015-6834 and fix it if it is affected.

What it is: CVE-2015-6834 is a critical use after free vulnerability in Php Php, published on 16 May 2016. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2015-6834 exists.

Affected product: Php Php. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2015-6834/ (Markdown: https://insights.sbomify.com/CVE-2015-6834/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2015-6834
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2015-6834
- OSV: https://osv.dev/vulnerability/CVE-2015-6834

---
From sbomify Insights: https://insights.sbomify.com/CVE-2015-6834/
Summaries are generated and may contain mistakes; the official description above is the record.