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Heap-Based Buffer Overflow RCE in Microsoft Edge (Chromium-based)
CVE-2026-56645 is a heap-based buffer overflow vulnerability in Microsoft Edge (Chromium-based) that can lead to remote code execution. The flaw affects Edge versions prior to 150.0.4078.48. Available information identifies the bug class as a heap memory corruption issue but does not provide the specific vulnerable component or function. Successful exploitation allows an unauthorized attacker to trigger memory corruption in the browser and execute attacker-controlled code in the context of the affected Edge process.
What it means and what to do now: patch path, interim mitigations, and the assume-compromise checklist.
What an attacker gets, and what they’ve been doing with it.
Successful exploitation can result in arbitrary code execution within the security context of the Microsoft Edge browser process. Depending on the browser sandbox boundary, the attacked user context, and any chained post-exploitation techniques, this may enable compromise of browser data, execution of additional payloads, and further system impact. The vulnerability is rated High severity with a CVSS base score of 8.8.
If you can’t patch tonight, do this now.
Apply the latest Microsoft Edge security updates on an expedited basis and restart the browser to activate the patched version. Until patching is complete, reduce exposure by limiting use of untrusted web content, restricting high-risk browsing activity, and enforcing browser hardening and application control policies where feasible. Enterprise defenders should prioritize rapid deployment because browser memory corruption vulnerabilities are commonly weaponized after disclosure.
Patch, then assume compromise.
Upgrade Microsoft Edge (Chromium-based) to version 150.0.4078.48 or later and ensure the vendor security update released in July 2026 is fully applied. Because Edge updates may not become effective until the browser is restarted, affected systems should be verified to be running the patched build after restart. Enterprises should also validate that any Edge-based runtimes using the same engine are updated in accordance with vendor guidance.
No public exploits tracked yet. Mallory keeps watching.
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
7 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.