CVE-2026-50891: Github.com/mickael kerjean/filestash Filestash Allows Attackers To Escalate Vulnerability

HIGH
Advisory Identifier: GHSA-rcqf-cpv9-g5jf
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CVSS 8.1
CWE-284
Published
Advisory Summary

CVE-2026-50891 is a HIGH (CVSS 8.1) filestash allows attackers to escalate vulnerability (CWE-284: Improper Access Control) affecting Github.com/mickael kerjean/filestash libraries in the Go ecosystem. The issue involves filestash allows attackers to escalate privileges via sending a crafted request. Remediation is available in the latest vendor maintenance releases.

CVE-2026-50891 at a Glance

CVE Identifier CVE-2026-50891
GHSA Identifier GHSA-rcqf-cpv9-g5jf
Severity HIGH
CVSS v3.1 Base Score 8.1
CWE Classification CWE-284: Improper Access Control
Affected Product Github.com/mickael kerjean/filestash
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 8.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2026-50891

To remediate this vulnerability, upgrade all affected Github.com/mickael kerjean/filestash dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

github.com/mickael-kerjean/filestash fixed: Latest secure release 
Upgrade github.com/mickael-kerjean/filestash to Latest secure release
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for github.com/mickael-kerjean/filestash

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-50891, inspect your project dependencies for Github.com/mickael kerjean/filestash:

inspect dependencies for github.com/mickael-kerjean/filestash

Analyze the terminal output to locate any version of Github.com/mickael kerjean/filestash in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-284: Improper Access Control, where the product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. In Github.com/mickael kerjean/filestash, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Incorrect access control in the /admin/api/config component of Filestash v0.4.0 allows attackers to escalate privileges via sending a crafted request.

CVE-2026-50891 Affected Github.com/mickael kerjean/filestash Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
github.com/mickael-kerjean/filestash
golang/github.com/mickael-kerjean/filestash
Go
≤ 0.2.2-0.20260827111952-cbcd1e96ebc7

References

NVD — CVE-2026-50891 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-50891
Github.com/mickael kerjean/filestash Source Repository REPOSITORY
https://gist.github.com/pyuysig/50dc365f54f95396bb67532f02b34bb0
Github.com/mickael kerjean/filestash Source Repository REPOSITORY
https://github.com/mickael-kerjean/filestash

Frequently Asked Questions

What is CVE-2026-50891?
CVE-2026-50891 is a security vulnerability in Github.com/mickael kerjean/filestash involving Filestash allows attackers to escalate privileges via sending a crafted request under CWE-284: Improper Access Control.
Which Github.com/mickael kerjean/filestash versions are affected?
Affected versions include releases prior to current release patches across affected packages: github.com/mickael-kerjean/filestash.
What version fixes CVE-2026-50891?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/mickael-kerjean/filestash affected?
Yes, github.com/mickael-kerjean/filestash is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2026-50891?
CVE-2026-50891 has a CVSS v3.1 base score of 8.1 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N.
What CWE is associated with CVE-2026-50891?
CVE-2026-50891 is classified under CWE-284: Improper Access Control (The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.).
How can I check Go dependencies for CVE-2026-50891?
Run the dependency tree command: 'inspect dependencies for github.com/mickael-kerjean/filestash'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-rcqf-cpv9-g5jf",
  "modified" : "2026-08-27T16:48:27Z",
  "published" : "2026-06-15T21:30:42Z",
  "aliases" : [ "CVE-2026-50891" ],
  "summary" : "Filestash allows attackers to escalate privileges via sending a crafted request",
  "details" : "Incorrect access control in the /admin/api/config component of Filestash v0.4.0 allows attackers to escalate privileges via sending a crafted request.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/mickael-kerjean/filestash"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "0.2.2-0.20260827111952-cbcd1e96ebc7"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-50891"
  }, {
    "type" : "WEB",
    "url" : "https://gist.github.com/pyuysig/50dc365f54f95396bb67532f02b34bb0"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/mickael-kerjean/filestash"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-284" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-08-27T16:48:27Z",
    "nvd_published_at" : "2026-06-15T20:16:32Z"
  }
}