Bug 2540688 (CVE-2026-96749)

Summary: CVE-2026-96749 pymongo: pymongo: Out-of-bounds write via integer overflow during BSON encoding
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: eglynn, jjoyce, jpretori, jschluet, lhh, mburns, mgarciac
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in pymongo. An integer overflow exists in the bundled native extension for Binary JSON (BSON) document encoding when processing an unusually large amount of data. An unprivileged attacker who can submit oversized data to an application for encoding can trigger an arithmetic overflow, resulting in a write outside the boundaries of an allocated memory buffer. This issue can lead to arbitrary code execution within the application process or a denial of service (DoS) via an application crash.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2542967, 2542968    
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Description OSIDB Bzimport 2026-09-24 18:33:56 UTC 
An integer overflow in the BSON document encoding component of the MongoDB Python Driver's bundled native extension may occur when a single document is built from an unusually large amount of caller-supplied data. Size arithmetic is performed in a signed 32-bit type, and the guard meant to catch the overflow is written in a form whose behavior is not defined by the C language standard. A party with no privileges who can place a very large value into data that an application encodes may, depending on how the native extension was built, cause a write outside the bounds of an allocated buffer inside the application's own process.