# CVE-2017-8923: Integer overflow in n/a

> Remote attackers can crash the PHP application by triggering a negative string length via integer overflow in zend_string_extend.

- **Severity:** Critical 9.8 (`CVSS:3.1/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:** 12 May 2017
- **Updated:** 27 Dec 2024
- **Also known as:** CLSA-2025-1749743304, CLSA-2025-1749743798, CLSA-2026-1772120065, GHSA-wrc8-jp87-rq8j, SUSE-SU-2022:0530-1, SUSE-SU-2022:0699-1, UBUNTU-CVE-2017-8923, openSUSE-SU-2022:0699-1

## What is CVE-2017-8923?

CVE-2017-8923 is a critical vulnerability in Php Php, published on 12 May 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The zend_string_extend function in Zend/zend_string.h in PHP through 7.1.5 does not prevent changes to string objects that result in a negative length, which allows remote attackers to cause a denial of service (application crash) or possibly have unspecified other impact by leveraging a script's use of .= with a long string.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2017-8923?

It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `php7` | SUSE:Linux Enterprise Module for Package Hub 15 SP3 | All versions | 7.4.6-3.32.1 |
| `php74` | SUSE:Linux Enterprise Module for Web and Scripting 12 | All versions | 7.4.6-1.33.1 |
| `php7` | SUSE:Linux Enterprise Module for Web and Scripting 15 SP3 | All versions | 7.4.6-3.32.1 |
| `php74` | SUSE:Linux Enterprise Software Development Kit 12 SP5 | All versions | 7.4.6-1.33.1 |
| `php7` | openSUSE:Leap 15.3 | All versions | 7.4.6-3.32.1 |
| `php7-test` | openSUSE:Leap 15.3 | All versions | 7.4.6-3.32.1 |

Products: Php Php.

## How do I fix CVE-2017-8923?

Apply the vendor's patch.

## Is CVE-2017-8923 being exploited?

There is no known exploitation of CVE-2017-8923 in the wild and no public exploit code.

## 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-2017-8923 and fix it if it is affected.

What it is: CVE-2017-8923 is a critical vulnerability in Php Php, published on 12 May 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2017-8923 in the wild and no public exploit code.

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-2017-8923/ (Markdown: https://insights.sbomify.com/CVE-2017-8923/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-8923
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-8923
- OSV: https://osv.dev/vulnerability/CVE-2017-8923

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-8923/
Summaries are generated and may contain mistakes; the official description above is the record.