Integer Overflow Vulnerability in libexpat Affects Expat Library from Google

CVE-2026-118370

What is CVE-2026-118370?

The libexpat library, through version 2.9.0, contains a significant vulnerability that can be exploited through a signed integer overflow in the storeAtts() function, located in xmlparse.c. This weakness enables attackers to deliver exceptionally large documents with a start tag possessing an extensive number of attributes—over 2^30—causing overflow in the variables attIndex and nPrefixes. Successful exploitation could result in crashing applications or corrupting vital heap memory, potentially leading to system instability.

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