CVE-2026-117897 in Firefox
Summary
by MITRE • 10/27/2026
Incorrect boundary conditions in the Layout: Tables component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, and Firefox ESR 153.6.
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Analysis
by VulDB Data Team • 10/27/2026
The identified vulnerability resides within the layout engine of Mozilla Firefox, specifically affecting the rendering logic for tables via the Layout: Tables component. This issue stems from incorrect boundary conditions during the calculation of table dimensions and cell positioning. In web browsers, the layout engine is responsible for translating HTML and CSS structures into visual representations on the screen. When processing complex or malformed table structures, the engine must strictly adhere to defined boundaries to ensure that elements do not overlap incorrectly or exceed their allocated space. The flaw indicates a failure in these boundary checks, allowing certain inputs to trigger unintended behavior within the rendering pipeline.
From a technical perspective, this type of vulnerability often involves memory safety issues such as out-of-bounds reads or writes, although it can also manifest as logic errors leading to incorrect layout calculations. In the context of browser engines like Gecko, which powers Firefox, boundary condition failures in critical components like table layouts can potentially be exploited for information disclosure if they lead to reading uninitialized memory or sensitive data structures adjacent to the affected buffer. Alternatively, such flaws might contribute to denial-of-service conditions by causing the rendering process to hang or crash due to infinite loops or invalid state transitions triggered by malformed HTML content containing nested tables with specific CSS properties.
The operational impact of this vulnerability is primarily related to user experience and potential security risks associated with malicious web pages. An attacker could craft a specially designed webpage utilizing complex table structures that exploit these boundary errors. If the flaw leads to memory corruption, it could potentially allow for remote code execution or data exfiltration, depending on how the browser handles the corrupted state during rendering. Even if limited to visual glitches, such vulnerabilities can be leveraged in phishing attacks by distorting page layouts to mimic legitimate sites more convincingly or to hide malicious elements behind incorrectly rendered boundaries.
This vulnerability has been addressed and fixed in Firefox version 159 as well as specific extended support release versions including ESR 115.44 and ESR 153.6. These updates include patches that correct the boundary condition logic within the table layout engine, ensuring that all dimensional calculations remain within safe limits regardless of input complexity. Users are strongly advised to update their browsers to these patched versions immediately to mitigate any potential exploitation vectors.
In terms of industry standards classification, this issue aligns with CWE-125 Out-of-bounds Read or CWE-787 Out-of-bounds Write if memory corruption is involved, reflecting a failure in boundary validation during data processing. From an offensive security perspective, such vulnerabilities are often categorized under ATT&CK techniques related to initial access via browser exploitation, specifically leveraging software vulnerabilities for code execution or reconnaissance through information leakage. Maintaining up-to-date software versions remains the most effective defense against these types of implementation flaws in web rendering engines.