Security readout for executives and security teams
Plain-English summary
A memory safety flaw in Microsoft Edge could let an attacker run code after a user opens attacker-controlled content. Successful exploitation could compromise data, change system state, or disrupt availability. Exploitation requires user interaction and is rated high severity, but the supplied sources do not establish active exploitation.
Executive priority
Treat this as a high-priority browser update, especially for privileged and high-value users. Prompt remediation is warranted because successful exploitation could run attacker code, although the required user interaction, high complexity, and lack of supplied active-exploitation evidence reduce immediate emergency pressure.
Technical view
CVE-2024-21399 is a Chromium-based Edge use-after-free vulnerability classified as CWE-416. Its CVSS 3.1 score is 8.3, with network reachability, high attack complexity, no privileges required, user interaction required, changed scope, and high confidentiality, integrity, and availability impacts.
Likely exposure
Exposure centers on endpoints running vulnerable Microsoft Edge builds where users may open attacker-controlled web content. The bundle lists version 1.0.0, but does not provide a reliable affected-version range or fixed build, so organizations should confirm applicability against Microsoft's advisory and their deployed inventory.
Exploitation context
The bundle marks the CVE as absent from KEV and gives exploit maturity as unproven. This does not prove exploitation is impossible or absent everywhere; it means the supplied evidence does not support claiming active exploitation. Attack complexity is high and user interaction is required.
Researcher notes
The supplied data supports a use-after-free classification but provides no affected component, root-cause detail, proof of concept, or dependable version range. The listed version 1.0.0 appears insufficient for exposure decisions. Researchers and vulnerability managers should use the Microsoft advisory as the authoritative source for build applicability and remediation.
Mitigation direction
- Review Microsoft's advisory for the applicable fixed Edge release.
- Update Microsoft Edge through the organization's approved browser patching process.
- Prioritize endpoints used for sensitive administration or access to high-value data.
- Apply normal web-content and browser isolation controls while patch status is confirmed.
Validation and detection
- Inventory installed Microsoft Edge versions across managed endpoints.
- Compare deployed builds with the affected and fixed versions in Microsoft's advisory.
- Confirm browser update policies successfully installed the approved security release.
- Re-scan endpoints and investigate devices that remain outdated or unmanaged.
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-2024-21399 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
- 8.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/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:C/C:H/I:H/A:H/E:U/RL:O/RC:C1.66microsoftVulnerability scoring details
Base CVSS 3.1 score
8.3HighVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/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.