Security readout for executives and security teams
Plain-English summary
CVE-2026-56645 is a high-severity Microsoft Edge Chromium-based browser flaw. A remote attacker could potentially run code if a user interacts with malicious network-delivered content. Business risk is meaningful because browsers are widely deployed and commonly exposed to untrusted web content.
Executive priority
Treat this as a priority browser patching issue. It is not reported as actively exploited in the supplied evidence, but successful exploitation could allow code execution with severe business impact.
Technical view
The issue is a heap-based buffer overflow, CWE-122, in Microsoft Edge Chromium-based. CVSS 3.1 is 8.8 with network attack vector, low complexity, no privileges required, user interaction required, unchanged scope, and high confidentiality, integrity, and availability impact.
Likely exposure
Organizations using Microsoft Edge Chromium-based may be exposed, especially managed endpoints where browser updates lag. The supplied affected data names Microsoft Edge Chromium-based version 1.0.0.0, but does not provide channel, platform, or build-range detail.
Exploitation context
The source bundle marks KEV as false and CVSS exploit maturity as unproven. No cited source in the bundle confirms active exploitation or public exploit availability. The scenario still matters because exploitation is network-reachable and requires only user interaction.
Researcher notes
Evidence is limited to the CVE description, CVSS vector, CWE, affected product entry, and MSRC advisory reference. The bundle does not identify the vulnerable component, proof-of-concept status, exploit primitives, or detailed fixed-version mapping.
Mitigation direction
- Apply the Microsoft Edge update referenced by the MSRC advisory.
- Confirm automatic browser updates are enabled across managed endpoints.
- Prioritize patching internet-facing user workstations and shared browsing environments.
- Check Microsoft guidance for exact fixed builds and platform-specific instructions.
Validation and detection
- Inventory Microsoft Edge Chromium-based versions across managed assets.
- Compare installed versions against the MSRC advisory’s affected and fixed build guidance.
- Verify update telemetry shows successful installation on endpoints.
- Review vulnerability scanner results for CVE-2026-56645 after patch deployment.
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-122: 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-2026-56645 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
- 8.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/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:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C2.85.9microsoftVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/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.
Heap-based Buffer Overflow
Heap-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.