CVE-2026-22693: Null Pointer Dereference in SubtableUnicodesCache::create leading to DoS
CVE-2026-22693 is a vulnerability in Null Pointer Dereference in SubtableUnicodesCache::create leading to DoS, rated Moderate by Microsoft, with a CVSS 3.1 base score of 5.3 (Medium). An attacker can exploit it remotely over the network, without any privileges and without user interaction. Microsoft has not reported exploitation in the wild. The EPSS model estimates a 0.45% probability of exploitation activity in the next 30 days, higher than 39% of all scored vulnerabilities. Microsoft released the fix on 11 January 2026 in the January 2026 Patch Tuesday. It affects 2 products in 2 product families (Open Source Software, Mariner).
Key facts
- CVE ID
- CVE-2026-22693
- Severity
- Medium CVSS 5.3
- Microsoft severity
- Moderate
- Exploited in the wild
- No
- Publicly disclosed
- No
- Weakness
- CWE-476
- EPSS
- 0.45% (percentile 39%)
- CISA KEV
- Not listed
- Released
- Last updated
- Patch Tuesday
- January 2026 Patch Tuesday
- Product families
- Open Source Software, Mariner
CVSS score and vector
Microsoft scores CVE-2026-22693 at 5.3 (temporal 4.9) using CVSS 3.1. Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U
| Metric | Value |
|---|---|
| Attack vector | Network |
| Attack complexity | Low |
| Privileges required | None |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality impact | None |
| Integrity impact | None |
| Availability impact | Low |
| Exploit code maturity | Unproven |
Affected products (2)
Open Source Software
| Product | Security update | Type | Fixed build | Restart |
|---|---|---|---|---|
| azl3 harfbuzz 8.3.0-4 on Azure Linux 3.0 | CBL-Mariner Releases | Security Update | 8.3.0-4 | No |
Mariner
| Product | Security update | Type | Fixed build | Restart |
|---|---|---|---|---|
| azl3 harfbuzz 8.3.0-3 on Azure Linux 3.0 | CBL-Mariner Releases | Security Update | 8.3.0-4 | No |
NIST NVD data
- NVD status
- Analyzed
- NVD CVSS
- 5.3 (MEDIUM)
- NVD weakness
- CWE-476
- Published to NVD
- NVD last modified
Affected configurations (CPE)
| Product | Vulnerable versions |
|---|---|
| harfbuzz | before 12.3.0 |
References
- https://github.com/harfbuzz/harfbuzz/commit/1265ff8d990284f04d8768f35b0e20ae5f60daae (Patch)
- https://github.com/harfbuzz/harfbuzz/security/advisories/GHSA-xvjr-f2r9-c7ww (Exploit, Mitigation, Vendor Advisory)
- http://www.openwall.com/lists/oss-security/2026/01/11/1 (Exploit, Mailing List, Patch, Third Party Advisory)
- http://www.openwall.com/lists/oss-security/2026/01/12/1 (Exploit, Mailing List, Patch, Third Party Advisory)
Revision history
| Version | Date | Description |
|---|---|---|
| 1.0 | Information published. | |
| 2.0 | Information published. | |
| 3.0 | Information published. | |
| 4.0 | Information published. | |
| 5.0 | Information published. |