Summary
AWS SDK for PHP has CloudFront Policy Document Injection via Special Characters
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.
Impacted versions: 3.11.7 - 3.371.3
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.
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.
The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths. Typical impact: varies by context: data corruption, logic bypass, or denial of service.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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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.
Frequently Asked Questions
- What is GHSA-27QH-8CXX-2CR5? GHSA-27QH-8CXX-2CR5 is a high-severity improper input validation vulnerability in aws/aws-sdk-php (composer), affecting versions >= 3.11.7, <= 3.371.3. It is fixed in 3.371.4. The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths.
- Which versions of aws/aws-sdk-php are affected by GHSA-27QH-8CXX-2CR5? aws/aws-sdk-php (composer) versions >= 3.11.7, <= 3.371.3 is affected.
- Is there a fix for GHSA-27QH-8CXX-2CR5? Yes. GHSA-27QH-8CXX-2CR5 is fixed in 3.371.4. Upgrade to this version or later.
- Is GHSA-27QH-8CXX-2CR5 exploitable, and should I be worried? Whether GHSA-27QH-8CXX-2CR5 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether GHSA-27QH-8CXX-2CR5 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix GHSA-27QH-8CXX-2CR5? Upgrade
aws/aws-sdk-phpto 3.371.4 or later.