GHSA-27qh-8cxx-2cr5 AWS SDK for PHP has CloudFront Policy Document Injection via Special Characters
Special characters in CloudFront signing inputs can alter policy documents, potentially bypassing access restrictions if input validation is missing.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is GHSA-27qh-8cxx-2cr5?
GHSA-27qh-8cxx-2cr5 is a code injection vulnerability in aws/aws-sdk-php, published on 27 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Summary
This notification is related to the CloudFront signing utilities in the AWS SDK for PHP, which are used to generate Amazon CloudFront signed URLs and signed cookies. A defense-in-depth enhancement has been implemented to improve handling of special characters, such as double quotes and backslashes, in input values.
Impact
The CloudFront signing utilities build policy documents that define access restrictions for signed URLs and cookies. If an application passes unsanitized input containing special characters to these utilities, the resulting policy document may not reflect the application's intended access restrictions. While the SDK was functioning safely within the requirements of the shared responsibility model, additional safeguards have been added to support secure customer implementations. Applications that already follow AWS security best practices for input validation are not impacted.
Impacted versions: 3.11.7 - 3.371.3
Patches
On 3/3/2026, an enhancement was made to the AWS SDK for PHP version 3.371.4. The enhancement ensures that special characters in input values are correctly handled. It is recommended to upgrade to the latest version.
Workarounds
No workarounds are needed, but customers should ensure that the application is following security best practices:
- Implement proper input validation in application code before passing values to CloudFront signing utilities
- Update to the latest AWS SDK release on a regular basis
- Follow AWS security best practices for SDK configuration
References
For any questions or comments about this advisory, it is recommended to contact AWS Security via the vulnerability reporting page or directly via email to [email protected]. Please do not create a public GitHub issue.
Acknowledgement
The Amazon Inspector Security Research team is thanked for identifying this issue and working through the coordinated process.
Which versions are affected by GHSA-27qh-8cxx-2cr5?
2 open source packages ship an affected version, including aws/aws-sdk-php.
| Package | Affected | Fixed in |
|---|---|---|
aws/aws-sdk-php Packagist | From 3.11.7 | 3.371.4 |
aws/aws-sdk-php Packagist | From 3.11.7 | 3.371.4 |
How do I fix GHSA-27qh-8cxx-2cr5?
Upgrade aws/aws-sdk-php to 3.371.4 or later.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is GHSA-27qh-8cxx-2cr5 being exploited?
There is no known exploitation of GHSA-27qh-8cxx-2cr5 in the wild and no public exploit code.