Answer in brief
CVE-2026-56857 records a Unknown severity vulnerability in Root.Mkdir(All) can follow junctions out of the root on Windows in os. The current sources do not mark it as known exploited. The current feed maps Go standard library/internal/syscall/windows (generic), Go standard library/os (generic), stdlib (go). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Go standard library/internal/syscall/windows (generic), Go standard library/os (generic), stdlib (go). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Go standard library/internal/syscall/windowsgeneric | >=0 <1.26.9 || >=1.27.0-0 <1.27.2 | 1.26.9, 1.27.2 |
| Go standard library/osgeneric | >=0 <1.26.9 || >=1.27.0-0 <1.27.2 | 1.26.9, 1.27.2 |
| stdlibgo | >=0 <1.26.9 >=1.27.0-0 <1.27.2 | 1.26.9, 1.27.2 |
Published upstream
Oct 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 8, 2026
On Windows, when the target of Root.Mkdir or Root.MkdirAll is a junction pointing to an empty location, the operation can create a directory at the junction target even when that target is located outside the root. This only applies to operations where the last path component is a junction (path/to/junction, but not path/junction/target).
Quoted source text, attributed separately from HOL analysis.