Skip to content
Patch Next
Sign inAdd to your agent

← Actionable
Low, CVSS 3.8

Zio has SubFileSystem Path Confinement Bypass via Unresolved .. Segment

GHSA-h39g-6x3c-7fq9

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (zio 0.22.2), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

Add to your agent

Affected packages

  • NuGet zio

    Affected
    <= 0.22.1
    Fixed in
    0.22.2

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
3.8 · CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N
EPSS
No dated EPSS signal available.
Source description

As published by the source; long descriptions are shortened.

Summary SubFileSystem fails to confine operations to its declared sub path when the input path is /../ (or equivalents /../, /..\\). This path passes all validation but resolves to the root of the parent filesystem, allowing directory level operations outside the intended boundary. Affected Component Zio.UPath.ValidateAndNormalize Zio.FileSystems.SubFileSystem UPath.ValidateAndNormalize has a trailing slash optimisation. When the input ends with / or \, and processParts is still false, the function strips the trailing separator and returns immediately before the .. resolution logic runs. The input /../ triggers this path: the trailing / is the last character, processParts has not been set (because .. as the first relative segment after root is specifically exempted), so the function returns /.. with the .. segment unresolved. The resulting UPath with FullName = "/.." is absolute, contains no control characters, and no colon so it passes FileSystem.ValidatePath without rejection. When…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 1 · created ·

    Published from ghsa record GHSA-h39g-6x3c-7fq9

Agent brief

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: GHSA-h39g-6x3c-7fq9

Advisory: Zio has SubFileSystem Path Confinement Bypass via Unresolved `..` Segment
IDs: GHSA-h39g-6x3c-7fq9
Record: https://patchnext.com/advisories/ghsa-h39g-6x3c-7fq9 (revision 1, source checked 26 Oct 2026, 17:04 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 3.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: zio 0.22.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet zio: affected <= 0.22.1; fixed in 0.22.2

## Suggested inspection (read-only)
- NuGet zio: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on zio.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-h39g-6x3c-7fq9 (GitHub-reviewed advisory GHSA-h39g-6x3c-7fq9 lists affected ranges: NuGet zio >=0 <=0.22.1)

Commands are suggestions: review each one before running it.

Loading voting…