Security readout for executives and security teams
Plain-English summary
CVE-2026-58276 is a high-severity Microsoft Edge browser flaw that could let an unauthenticated remote attacker run code if a user interacts with malicious content. The public bundle does not show active exploitation, but browser remote-code-execution issues warrant prompt enterprise patching.
Executive priority
Treat as a near-term patching priority for endpoint teams. It is not KEV-listed in the bundle, but the potential impact is full code execution through a commonly used browser.
Technical view
The issue is a CWE-416 use-after-free in Microsoft Edge (Chromium-based). CVSS 3.1 is 7.5: network reachable, high attack complexity, no privileges required, user interaction required, and high confidentiality, integrity, and availability impact.
Likely exposure
Organizations with Microsoft Edge (Chromium-based) installed on managed or unmanaged endpoints may be exposed, especially where browser updates are delayed or users can access untrusted web content.
Exploitation context
The source bundle lists KEV as false and CVSS exploit maturity as unproven. No provided source supports active exploitation. Successful attack requires user interaction and high complexity.
Researcher notes
Affected data in the bundle names Microsoft Edge (Chromium-based) and version 1.0.0.0, but does not clarify version ranges or fixed builds. Avoid assuming Chromium-wide impact without vendor confirmation.
Mitigation direction
- Apply the Microsoft Edge update referenced by MSRC guidance.
- Verify Edge auto-update is enabled across managed endpoints.
- Prioritize internet-facing and high-risk user workstations.
- Check Microsoft guidance for fixed version details not included in the bundle.
Validation and detection
- Inventory Microsoft Edge (Chromium-based) installations and versions.
- Confirm endpoints received the MSRC-addressing update for CVE-2026-58276.
- Review browser update policy enforcement and failure reports.
- Monitor vulnerability scanners for remaining Edge detections.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-416: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-58276 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C1.65.9microsoftVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- Microsoft Edge (Chromium-based) Remote Code Execution VulnerabilityCVE reference, microsoft · vendor-advisory, patch
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Use After Free
Use After Free represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.