CVE-2026-56857
Go standard library os
- Go standard library os
- Critical
- CVSS 9.8
- EPSS 0.55%
- Fixed version listed
What to do
Fixed version listed
Affected products
| Product | Affected | Fixed in |
|---|---|---|
| Go standard library os (windows) | before 1.26.9; from 1.27.0-0, before 1.27.2 | 1.26.9, 1.27.2 |
| Go standard library internal/syscall/windows (windows) | before 1.26.9; from 1.27.0-0, before 1.27.2 | 1.26.9, 1.27.2 |
Scores and signals
- Exploitation
- No known exploitation
- Severity
- Critical, CVSS 9.8 (v3.1, scored by CISA-ADP)
- EPSS
- 0.55% chance of exploitation in the next 30 days (EPSS from FIRST, as of Oct 25, 2026)
- CISA's SSVC decision points
- Exploitation: none. Automatable: yes. Technical impact: total. As of Oct 9, 2026.
- Weakness
- CWE-1386: Insecure Operation on Windows Junction / Mount Point
- Vendor
- Go standard library, os
Timeline
- First listed as critical by cve.now. Affected and fixed versions come from the CVE record, once one is published.