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CVE-2025-4918 is a critical out-of-bounds access vulnerability in Mozilla Firefox's JavaScript engine that occurs when resolving JavaScript Promise objects. According to the provided advisory and supporting reporting, an attacker can trigger an out-of-bounds read or write on a JavaScript Promise object during Promise resolution. The issue was demonstrated as a zero-day at Pwn2Own Berlin 2025 by researchers Edouard Bochin and Tao Yan. Mozilla fixed the flaw in Firefox 138.0.4, Firefox ESR 128.10.1, Firefox ESR 115.23.1, Thunderbird 128.10.2, and Thunderbird 138.0.2.
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18 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
An out-of-bounds access vulnerability in Firefox related to resolving Promise objects, exploited as a zero-day at Pwn2Own Berlin.
An out-of-bounds access vulnerability in Firefox when resolving Promise objects, allowing attackers to read or write on a JavaScript Promise object, potentially leading to sensitive data access or code execution.
A critical out-of-bounds read/write vulnerability in the Firefox JavaScript engine when resolving Promise objects, demonstrated at Pwn2Own Berlin 2025.
A zero-day vulnerability in Mozilla Firefox web browser, patched in version 138.0.4 and corresponding ESR and Android versions.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
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Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.