Microsoft Edge (Chromium-based): Heap-based buffer overflow enables code execution
Summary
A heap-based buffer overflow (CWE-122) in Microsoft Edge (Chromium-based) allows a remote attacker without privileges to execute code. The victim must take an action, such as visiting a malicious or compromised web page. The CVSS base score is 8.8 (High), but the fixed build is not yet confirmed.
Affected
- Microsoft Edge (Chromium-based): according to the CNA record, 1.0.0.0 up to but excluding 154.0.4258.37. This range is provisional and not yet confirmed by MSRC.
Fixed in
- Unknown. Aggregators name 154.0.4258.37, but the MSRC Security Update Guide lists a later security build, 154.0.4258.62 (Oct 26, 2026). Verify the fixed build on MSRC. - Until then, install the newest Stable Edge build.
Workaround
- No vendor-documented workaround. Patching is the only fix. - Interim measures (general practice, not from vendor sources): ensure Edge auto-update is not blocked by policy, enforce updates via Intune or WSUS, consider Enhanced Security Mode and SmartScreen, and restrict local admin rights.
Exploitation
- Not known to be exploited. - CISA SSVC: exploitation none, automatable no, technical impact total. - Not listed in CISA KEV according to aggregator sources. - EPSS 0.59 % (percentile 48). - No public proof of concept found.
Our recommendation
- Update Microsoft Edge on all Windows clients to the newest Stable build now, and confirm the fixed build on MSRC. - Check that Edge auto-update is not disabled or delayed by policy, and enforce updates via Intune or WSUS. - Prioritise fleets with delayed updates and users who browse untrusted sites. - Monitor endpoint protection for suspicious browser crashes or code execution alerts.
Information from Microsoft (Patch Tuesday October 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- MSRC Security Update Guide: CVE-2026-96199 msrc.microsoft.com
- MSRC Security Update Guide msrc.microsoft.com
- Microsoft Edge stable channel release notes archive learn.microsoft.com
- Tenable plugin for Microsoft Edge www.tenable.com
- Strix CVE record CVE-2026-96199 www.strix.ai
- OffSeq threat record (aggregator) radar.offseq.com
- Vulners CVE record CVE-2026-96199 vulners.com
- GitHub CVE issue tracker entry github.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 31 Oct 2026, 09:03.
Original description (NVD)
Heap-based buffer overflow in Microsoft Edge (Chromium-based) allows an unauthorized attacker to execute code over a network.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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