CVE-2026-8956
Analyzed Analyzed - Analysis Complete
Integer Overflow in Firefox Networking JAR Component

Publication date: 2026-05-19

Last updated on: 2026-05-20

Assigner: Mozilla Corporation

Description
Integer overflow in the Networking: JAR component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
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Meta Information
Published
2026-05-19
Last Modified
2026-05-20
Generated
2026-06-10
AI Q&A
2026-05-19
EPSS Evaluated
2026-06-08
NVD
CVE-2026-8956
EUVD
EUVD-2026-30904
Affected Vendors & Products
Showing 4 associated CPEs
Vendor Product Version / Range
mozilla firefox to 151.0.0 (exc)
mozilla firefox to 140.11.0 (exc)
mozilla thunderbird to 151.0.0 (exc)
mozilla thunderbird to 140.11 (exc)
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Exploitability
CWE
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KEV
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CWE ID Description
CWE-190 The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
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Executive Summary

This vulnerability is an integer overflow in the Networking: JAR component of Mozilla Firefox. An integer overflow occurs when a calculation exceeds the maximum size that can be stored in an integer variable, potentially leading to unexpected behavior or security issues. This specific vulnerability was addressed and fixed in Firefox version 151 and Firefox ESR 140.11.

Impact Analysis

An integer overflow in a networking component like the JAR handler could potentially be exploited to cause crashes, memory corruption, or other unintended behavior in the browser. This might allow attackers to execute arbitrary code, disrupt service, or compromise the security of the affected system. However, specific impacts are not detailed in the provided information.

Mitigation Strategies

The vulnerability was fixed in Firefox 151 and Firefox ESR 140.11. To mitigate this vulnerability, you should update your Firefox or Firefox ESR browser to at least these versions.

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