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HIGH severity

CVE-2026-57991 — Edge Chromium

HIGH

CVE-2026-57991 is a high-severity (CVSS 7.4) CWE-59 vulnerability in microsoft edge chromium. A fix is available — see the affected versions and patch details below.

Improper link resolution before file access ('link following') in Microsoft Edge (Chromium-based) allows an unauthorized attacker to disclose information over a network.

Published
Updated
Affected
1 product
Patched
See advisory
Exploits
None indexed
Exploitation data as of Oct 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-57991.

EPSS Exploitation Probability

via FIRST.org ↗
1.0%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs63th percentile — riskier than 63% of all scored CVEsHighest risk
0.24%0.68%1.11%1.54%0.7%1.0%1.0%1.0%Aug 26Oct 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2026-57991 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 384,993 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Description

Improper link resolution before file access ('link following') in Microsoft Edge (Chromium-based) allows an unauthorized attacker to disclose information over a network.

Affected Products

1 product · 1 configurations
Application
edge chromiummicrosoft
< 150.0.4078.48
range

Detection & mitigation playbook

Vendor / appliance

  1. Detect

    Inventory every microsoft edge chromium deployment and check each version against the affected-products list above.

  2. Fix

    Apply the microsoft edge chromium security patch or hotfix for CVE-2026-57991 on the affected version, following the vendor advisory for your exact build.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.

Frequently Asked Questions

Improper link resolution before file access ('link following') in Microsoft Edge (Chromium-based) allows an unauthorized attacker to disclose information over a network.
O3 Security · Runtime Protection

Is CVE-2026-57991 being exploited in your environment?

Detect and block the exploit chain at execution, on systems you cannot patch yet.

Protect my workloads How runtime protection works
CVE-2026-57991: Edge Chromium (High 7.4)