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CVE-2026-57977 Microsoft CVE debrief

CVE-2026-57977 is a high-severity vulnerability in Microsoft Edge (Chromium-based) that allows unauthorized attackers to perform spoofing over a network by improper neutralization of input during web page generation, also known as cross-site scripting. This vulnerability has a CVSS score of 7.1 and is classified as HIGH severity. It exists in the Microsoft Edge (Chromium-based) browser and allows an unauthorized attacker to perform spoofing over a network. Users of Microsoft Edge (Chromium-based) should apply patches immediately to prevent potential spoofing attacks. The vulnerability was published on 2026-07-03T21:17:01.193Z and was last modified on 2026-07-07T13:14:18.280Z.

Vendor
Microsoft
Product
Microsoft Edge (Chromium-based)
CVSS
HIGH 7.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-03
Original CVE updated
2026-07-07
Advisory published
2026-07-03
Advisory updated
2026-07-07

Who should care

Users of Microsoft Edge (Chromium-based) should apply patches immediately to prevent potential spoofing attacks. This includes administrators and users who utilize Microsoft Edge (Chromium-based) for browsing. The vulnerability allows unauthorized attackers to perform spoofing over a network, which could lead to phishing or other malicious activities.

Technical summary

The vulnerability has a CVSS score of 7.1 and is classified as HIGH severity. It exists in the Microsoft Edge (Chromium-based) browser and allows an unauthorized attacker to perform spoofing over a network by improper neutralization of input during web page generation. This vulnerability is also known as cross-site scripting. Users should verify their systems and apply patches provided by Microsoft.

Defensive priority

High priority, apply patches immediately and monitor for suspicious activity

Recommended defensive actions

  • Apply patches provided by Microsoft
  • Ensure Microsoft Edge (Chromium-based) is updated to the latest version
  • Monitor for suspicious activity
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record was published on 2026-07-03T21:17:01.193Z and was last modified on 2026-07-07T13:14:18.280Z. The NVD entry is currently Analyzed. This information is based on the NVD entry and the CVE record. The vulnerability affects Microsoft Edge (Chromium-based) and allows an unauthorized attacker to perform spoofing over a network by improper neutralization of input during web page generation. The CVSS score is 7.1, classified as HIGH severity. Users should verify their systems and apply patches provided by Microsoft.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-57977 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-57977

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-57977 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-57977

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.