Critical Memory Allocation Vulnerability in Expat Package: CVE-2025-59375
Summary
ALSA-2025:19403: Important: expat security update. Affects expat versions < 2.7.1-1.el10_0.3. Fixed in 2.7.1-1.el10_0.3. How to fix ↓
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Background
Expat is a widely used C library designed for parsing XML documents. It is known for its efficiency and flexibility, making it a popular choice among developers for handling XML data. However, the library has been found to have a critical vulnerability that allows attackers to exploit memory allocation processes, potentially leading to denial of service or other malicious outcomes.
Vulnerability Detail
The vulnerability identified as CVE-2025-59375 allows attackers to trigger large dynamic memory allocations by submitting a small XML document for parsing. This can lead to excessive memory usage, potentially crashing the application or causing it to behave unpredictably. The issue arises from improper handling of memory allocation requests, which can be exploited by crafting specific XML inputs.
How To Fix
Minimum fixed version
2.7.1-1.el10_0.3
This is the first release that contains the fix.
sudo dnf update expatTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
If immediate updating is not feasible, consider implementing input validation to restrict the size and complexity of XML documents being processed. This can help mitigate the risk of exploitation until the package can be updated.
Conclusion
The Expat library has a critical vulnerability (CVE-2025-59375) that can be exploited through specially crafted XML documents, leading to significant memory allocation issues. It is crucial to update to the patched version to mitigate risks. For those unable to update immediately, implementing input validation can serve as a temporary measure.
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FAQ
CVE-2025-59375 is a vulnerability in the Expat library that allows attackers to exploit memory allocation processes through specially crafted XML documents.
You can use Vulert's playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
The vulnerability can lead to denial of service, application crashes, or unpredictable behavior due to excessive memory usage.
Yes, a patch is available in version 2.7.1-1.el10_0.3 of the Expat package. Updating to this version will resolve the issue.
Implement input validation to restrict the size and complexity of XML documents processed by your application as a temporary workaround.
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