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CVE-2019-17026 is a critical type confusion vulnerability in Mozilla’s IonMonkey JavaScript JIT compiler affecting Firefox, Firefox ESR, and Thunderbird. The flaw is caused by incorrect alias information when setting array elements in IonMonkey, which can result in type confusion during JIT-optimized JavaScript execution. An attacker can trigger the condition with crafted web content and achieve remote code execution in the context of the affected application. The issue was reported as exploited in targeted attacks in the wild. Affected versions include Firefox prior to 72.0.1, Firefox ESR prior to 68.4.1, and Thunderbird prior to 68.4.1.
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1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos (1 hidden).
This repository contains a proof-of-concept exploit for CVE-2019-17026, a type confusion vulnerability in Firefox's IonMonkey JIT engine. The exploit is implemented as a single HTML file (calc.html) containing JavaScript code that manipulates JavaScript arrays to achieve out-of-bounds access, leading to arbitrary read/write primitives. These primitives are then used to locate and overwrite JIT-compiled code pointers, allowing the attacker to execute arbitrary shellcode (JIT-sprayed in the 'shellcode' function). The exploit requires the target to disable Firefox's content sandbox (security.sandbox.content.level=0) and works on Firefox versions prior to 72.0.1. The README provides context, references, and usage notes. No sandbox escape is included, but the exploit demonstrates reliable code execution in the renderer process. The repository is structured simply, with a README and a single exploit HTML file.
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
7 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A Firefox 0-day mentioned as part of the 'Double Star' attack chain alongside CVE-2020-0674.
A Firefox vulnerability exploited in a DarkHotel-attributed campaign targeting Chinese government agencies and used to deliver Gh0st RAT.
A Firefox zero-day mentioned only as part of the Double Star attack chain alongside CVE-2020-0674.
A Firefox vulnerability mentioned as part of a sandbox escape chain together with CVE-2020-0674.
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.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.