Security readout for executives and security teams
Plain-English summary
This is a Windows privilege escalation issue tied to user account profile pictures. An attacker already on an affected machine with low privileges could potentially gain higher privileges. It is not described as remotely exploitable from the internet, but the impact is high if used after initial compromise.
Executive priority
Treat as high priority in Windows patch management, especially on multi-user systems. It is less urgent than unauthenticated remote code execution, but high-impact privilege escalation can materially worsen a breach once an attacker has a foothold.
Technical view
CVE-2021-26426 is a local elevation-of-privilege vulnerability in Windows User Account Profile Picture handling. CVSS 3.1 is 7.0 with local attack vector, high complexity, low privileges required, no user interaction, unchanged scope, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is likely on unpatched Windows 8.1, Windows 10 versions 1507 through 21H1, Windows Server 2012, 2012 R2, 2016, 2019, and Server Core variants listed by Microsoft.
Exploitation context
The source bundle does not show CISA KEV listing or cited active exploitation. The CVSS vector indicates exploitation requires local access and low privileges, making this mainly a post-compromise or insider-risk escalation path.
Researcher notes
Evidence is sparse beyond Microsoft’s advisory metadata. The supplied CPEs include apparent version-label inconsistencies, so validate exposure against MSRC product/build guidance rather than CPE strings alone. No exploit details or active exploitation are supported by the bundle.
Mitigation direction
- Apply Microsoft security updates referenced by the MSRC advisory.
- Prioritize shared workstations, RDS hosts, and servers with many local users.
- Check Microsoft guidance for exact fixed builds and update packages.
- Reduce unnecessary local user access on affected Windows systems.
Validation and detection
- Inventory Windows versions and builds against the affected product list.
- Confirm installed updates meet Microsoft’s fixed-build guidance.
- Review vulnerability scanner findings for CVE-2021-26426 coverage.
- Validate exceptions manually where CPE data appears inconsistent.
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.
Privilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-26426 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 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/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.
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:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C15.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7HighVector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Source materials
- CVE List V5 sourceCVE List V5
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26426CVE reference · x_refsource_MISC
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.