CVE-2026-119196: pyasn1: Quadratic CPU consumption in constructed BIT STRING decoding
CVE-2026-119196 is a vulnerability in pyasn1: Quadratic CPU consumption in constructed BIT STRING decoding, rated Important by Microsoft, with a CVSS 3.1 base score of 7.5 (High). 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 0.43% probability of exploitation activity in the next 30 days, higher than 37% of all scored vulnerabilities. Microsoft released the fix on 31 October 2026, outside Patch Tuesday. It affects 1 product in 1 product family (Open Source Software).
Key facts
- CVE ID
- CVE-2026-119196
- Severity
- High CVSS 7.5
- Microsoft severity
- Important
- Exploited in the wild
- No
- Publicly disclosed
- No
- Weakness
- CWE-407
- EPSS
- 0.43% (percentile 37%)
- CISA KEV
- Not listed
- Released
- Last updated
- Patch Tuesday
- October 2026 Patch Tuesday
- Product families
- Open Source Software
CVSS score and vector
Microsoft scores CVE-2026-119196 at 7.5 (temporal 7.5) using CVSS 3.1. Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
| Metric | Value |
|---|---|
| Attack vector | Network |
| Attack complexity | Low |
| Privileges required | None |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality impact | None |
| Integrity impact | None |
| Availability impact | High |
Affected products (1)
Open Source Software
| Product | Security update | Type | Fixed build | Restart |
|---|---|---|---|---|
| azl3 python-pyasn1 0.4.8-3 on Azure Linux 3.0 | Release Notes | Security Update |
NIST NVD data
- NVD status
- Awaiting Analysis
- NVD CVSS
- 7.5 (HIGH)
- NVD weakness
- CWE-407
- Published to NVD
- NVD last modified
References
Revision history
| Version | Date | Description |
|---|---|---|
| 1.0 | Information published. |