CVE-2026-27913: Windows BitLocker Security Feature Bypass Vulnerability
CVE-2026-27913 is a security feature bypass vulnerability in Windows BitLocker, rated Important by Microsoft, with a CVSS 3.1 base score of 7.7 (High). An attacker can exploit it by an attacker with local access, without any privileges and without user interaction. Microsoft has not reported exploitation in the wild and rates exploitation as more likely. The EPSS model estimates a 0.30% probability of exploitation activity in the next 30 days, higher than 23% of all scored vulnerabilities. Microsoft released the fix on 14 April 2026 in the April 2026 Patch Tuesday, delivered through 6 security updates (KB5082123, KB5082060, KB5082198, KB5082142 and more). It affects 11 products in 2 product families (Windows, ESU).
Key facts
- CVE ID
- CVE-2026-27913
- Severity
- High CVSS 7.7
- Microsoft severity
- Important
- Impact
- Security Feature Bypass
- Exploited in the wild
- No
- Publicly disclosed
- No
- Exploitation likelihood
- More Likely
- Weakness
- CWE-20
- EPSS
- 0.30% (percentile 23%)
- CISA KEV
- Not listed
- Released
- Last updated
- Patch Tuesday
- April 2026 Patch Tuesday
- Product families
- Windows, ESU
CVSS score and vector
Microsoft scores CVE-2026-27913 at 7.7 (temporal 6.7) using CVSS 3.1. Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C
| Metric | Value |
|---|---|
| Attack vector | Local |
| Attack complexity | Low |
| Privileges required | None |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality impact | High |
| Integrity impact | High |
| Availability impact | None |
| Exploit code maturity | Unproven |
| Remediation level | Official fix |
| Report confidence | Confirmed |
Description
Improper input validation in Windows BitLocker allows an unauthorized attacker to bypass a security feature locally.
Frequently asked questions (Microsoft)
What kind of security feature could be bypassed by successfully exploiting this vulnerability?
An attacker who successfully exploited this vulnerability could bypass Secure Boot.
Affected products (11)
Windows
| Product | Security update | Type | Fixed build | Restart |
|---|---|---|---|---|
| Windows Server 2019 | KB5082123 | Security Update | 10.0.17763.8644 | Yes |
| Windows Server 2022, 23H2 Edition (Server Core installation) | KB5082060 | Security Update | 10.0.25398.2274 | Yes |
| Windows Server 2016 | KB5082198 | Security Update | 10.0.14393.9060 | Yes |
| Windows Server 2016 (Server Core installation) | KB5082198 | Security Update | 10.0.14393.9060 | Yes |
| Windows Server 2019 (Server Core installation) | KB5082123 | Security Update | 10.0.17763.8644 | Yes |
| Windows Server 2022 | KB5082142 | Security Update | 10.0.20348.5020 | Yes |
| Windows Server 2022 (Server Core installation) | KB5082142 | Security Update | 10.0.20348.5020 | Yes |
ESU
| Product | Security update | Type | Fixed build | Restart |
|---|---|---|---|---|
| Windows Server 2012 (Server Core installation) | KB5082127 | Monthly Rollup | 6.2.9200.26026 | Yes |
| Windows Server 2012 | KB5082127 | Monthly Rollup | 6.2.9200.26026 | Yes |
| Windows Server 2012 R2 | KB5082126 | Monthly Rollup | 6.3.9600.23132 | Yes |
| Windows Server 2012 R2 (Server Core installation) | KB5082126 | Monthly Rollup | 6.3.9600.23132 | Yes |
Security updates (6)
NIST NVD data
- NVD status
- Analyzed
- NVD CVSS
- 7.7 (HIGH)
- NVD weakness
- CWE-20
- Published to NVD
- NVD last modified
Affected configurations (CPE)
| Product | Vulnerable versions |
|---|---|
| windows server 2012 | all listed versions |
| windows server 2012 r2 | all listed versions |
| windows server 2016 | before 10.0.14393.9060 |
| windows server 2019 | before 10.0.17763.8644 |
| windows server 2022 | before 10.0.20348.5020 |
| windows server 2022 23h2 | before 10.0.25398.2274 |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-27913 (Vendor Advisory)
Acknowledgments
Revision history
| Version | Date | Description |
|---|---|---|
| 1.0 | Information published. |