PatchSiren

PatchSiren cyber security CVE debrief

CVE-2026-58616 Microsoft CVE debrief

A race condition vulnerability in Copilot Chat (Microsoft Edge) allows an authorized attacker to disclose information over a network. The vulnerability has a CVSS score of 4.4 and is classified as MEDIUM severity. This vulnerability affects Microsoft Edge Chromium and Copilot Chat deployments. Defenders and security teams should assess exposure and prioritize patching to prevent potential information disclosure. The vulnerability is a race condition that allows an authorized attacker to disclose information over a network. The CVSS vector is CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N. To mitigate this vulnerability, defenders should prioritize verifying and applying patches for

Vendor
Microsoft
Product
Edge Chromium
CVSS
MEDIUM 4.4
CISA KEV
Not listed in stored evidence
Original CVE published
2026-08-28
Original CVE updated
2026-09-11
Advisory published
2026-08-28
Advisory updated
2026-09-11

Who should care

Defenders and security teams responsible for Microsoft Edge Chromium and Copilot Chat deployments should assess exposure and prioritize patching to prevent potential information disclosure.

Why it matters

Defenders should prioritize verifying and applying patches for Microsoft Edge Chromium, especially in environments where Copilot Chat is used, to prevent potential information disclosure. The vulnerability has a CVSS score of 4.4 and is classified as MEDIUM severity.

  • Potential information disclosure over the network
  • Requires verification of patch application and configuration updates
  • May impact environments where Copilot Chat is used

Technical summary

The vulnerability is a race condition in Copilot Chat (Microsoft Edge) that allows an authorized attacker to disclose information over a network. The CVSS vector is CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N. This vulnerability affects Microsoft Edge Chromium and Copilot Chat deployments. Defenders should prioritize verifying and applying patches for Microsoft Edge Chromium, especially in environments where Copilot Chat is used, to prevent potential information disclosure. The vulnerability has a CVSS score of 4.4 and is classified as MEDIUM severity. To address

Defensive priority

Defenders should prioritize verifying and applying patches for Microsoft Edge Chromium, especially in environments where Copilot Chat is used, to prevent potential information disclosure.

Recommended defensive actions

  • Verify and apply patches for Microsoft Edge Chromium
  • Review and update configurations for Copilot Chat
  • Monitor for potential information disclosure attempts

Evidence notes

The vulnerability is described as a race condition in Copilot Chat (Microsoft Edge) that allows an authorized attacker to disclose information over a network. The CVSS vector is CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-58616 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-58616

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

  • CVE-2026-58616 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-58616

    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.