CVE-2026-44423: Github.com/shellhub io/shellhub Uid` That Discloses SSH Session Vulnerability

MODERATE
Advisory Identifier: GHSA-9w9c-9w8m-w89q
CVSS 6.5
CWE-639
Published
Advisory Summary

CVE-2026-44423 is a MODERATE (CVSS 6.5) uid` that discloses ssh session vulnerability (CWE-639: Authorization Bypass Through User-Controlled Key) affecting Github.com/shellhub io/shellhub libraries in the Go ecosystem. The issue involves uid` that discloses ssh session data. Remediation is available by upgrading affected packages to version 0.24.2.

CVE-2026-44423 at a Glance

CVE Identifier CVE-2026-44423
GHSA Identifier GHSA-9w9c-9w8m-w89q
Severity MODERATE
CVSS v3.1 Base Score 6.5
CWE Classification CWE-639: Authorization Bypass Through User-Controlled Key
Affected Product Github.com/shellhub io/shellhub
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 6.5

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:N/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 None (I:N)
Availability None (A:N)

How to Fix CVE-2026-44423

To remediate this vulnerability, upgrade all affected Github.com/shellhub io/shellhub 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/shellhub-io/shellhub fixed: 0.24.2
Upgrade github.com/shellhub-io/shellhub to 0.24.2
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/shellhub-io/shellhub

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-44423, inspect your project dependencies for Github.com/shellhub io/shellhub:

inspect dependencies for github.com/shellhub-io/shellhub

Analyze the terminal output to locate any version of Github.com/shellhub io/shellhub in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.24.2), 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-639: Authorization Bypass Through User-Controlled Key, where the system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. In Github.com/shellhub io/shellhub, 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

## Summary `GET /api/sessions/:uid` returns the full session object for any authenticated caller, without scoping by the caller's tenant. An authenticated user can read session records (SSH username, device UID, remote IP, terminal type, authenticated flag, timestamps) belonging to any other namespace. ## Severity **CVSS 3.1: 7.5 (High)** CWE-639 ## Affected versions ShellHub Community v0.24.1 (by code inspection — same vulnerable pattern as `GetDevice`). Not plant-reproducible without an active SSH session, but the flaw is structurally identical and confirmed via static analysis. ## Root cause `api/services/session.go:37-44` — `GetSession` resolves the session by UID without any tenant filter: ```go func (s *service) GetSession(ctx context.Context, uid models.UID) (*models.Session, error) { session, err := s.store.SessionResolve(ctx, store.SessionUIDResolver, string(uid)) // ⚠️ missing: s.store.Options().InNamespace(tenant) ... } ``` The `Authorize` middleware only verifies presence of a tenant in the context, not ownership of the requested session. ## Proof of concept Pre-requisite: attacker has any valid user account and has obtained a session UID from the victim tenant (UIDs may leak via logs, shared session recordings, UI URLs, or through the device IDOR in the companion advisory since sessions reference devices by UID). ```bash ATTACKER_TOKEN=$(curl -s -X POST http://target/api/login \ -H 'Content-Type: application/json' \ -d '{"username":"attacker","password":"..."}' | jq -r .token) # Attempt cross-tenant read curl -i "http://target/api/sessions/<victim-session-uid>" \ -H "Authorization: Bearer $ATTACKER_TOKEN" # Expected (fixed): HTTP 403/404 # Observed (v0.24.1): HTTP 200 + full session JSON ``` ## Impact - Cross-tenant disclosure of SSH session data: target username, device UID, remote IP, authenticated status, session type, terminal, position (geolocation), started_at / last_seen timestamps. - Enables reconnaissance of other tenants' active users and systems; combined with session recording features, can enable deeper recon. ## Suggested fix `api/services/session.go` — apply `InNamespace` in `GetSession`: ```go func (s *service) GetSession(ctx context.Context, uid models.UID) (*models.Session, error) { tenant := gateway.TenantFromContext(ctx) opts := []store.QueryOption{} if tenant != nil { opts = append(opts, s.store.Options().InNamespace(tenant.ID)) } session, err := s.store.SessionResolve(ctx, store.SessionUIDResolver, string(uid), opts...) ... } ```

CVE-2026-44423 Affected Github.com/shellhub io/shellhub Versions

1 component(s)
Fixed Versions:
0.24.2
Product / Package Ecosystem Affected Versions Fixed Version
github.com/shellhub-io/shellhub
Go
< 0.24.2
0.24.2

References

Frequently Asked Questions

What is CVE-2026-44423?
CVE-2026-44423 is a security vulnerability in Github.com/shellhub io/shellhub involving uid` that discloses SSH session data under CWE-639: Authorization Bypass Through User-Controlled Key.
Which Github.com/shellhub io/shellhub versions are affected?
Affected versions include releases prior to 0.24.2 across affected packages: github.com/shellhub-io/shellhub.
What version fixes CVE-2026-44423?
Upgrading to 0.24.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/shellhub-io/shellhub affected?
Yes, github.com/shellhub-io/shellhub is affected in releases prior to 0.24.2. Upgrade your dependency to 0.24.2 or later.
What is the CVSS score of CVE-2026-44423?
CVE-2026-44423 has a CVSS v3.1 base score of 6.5 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.
What CWE is associated with CVE-2026-44423?
CVE-2026-44423 is classified under CWE-639: Authorization Bypass Through User-Controlled Key (The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.).
How can I check Go dependencies for CVE-2026-44423?
Run the dependency tree command: 'inspect dependencies for github.com/shellhub-io/shellhub'. 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
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-9w9c-9w8m-w89q",
  "modified" : "2026-07-21T13:57:29Z",
  "published" : "2026-05-06T23:22:39Z",
  "aliases" : [ "CVE-2026-44423" ],
  "summary" : "ShellHub has cross-tenant IDOR in `GET /api/sessions/:uid` that discloses SSH session data",
  "details" : "## Summary\n`GET /api/sessions/:uid` returns the full session object for any authenticated caller, without scoping by the caller's tenant. An authenticated user can read session records (SSH username, device UID, remote IP, terminal type, authenticated flag, timestamps) belonging to any other namespace.\n\n## Severity\n**CVSS 3.1: 7.5 (High)** \nCWE-639\n\n## Affected versions\nShellHub Community v0.24.1 (by code inspection — same vulnerable pattern as `GetDevice`). Not plant-reproducible without an active SSH session, but the flaw is structurally identical and confirmed via static analysis.\n\n## Root cause\n`api/services/session.go:37-44` — `GetSession` resolves the session by UID without any tenant filter:\n\n  ```go\n  func (s *service) GetSession(ctx context.Context, uid models.UID) (*models.Session, error) {\n      session, err := s.store.SessionResolve(ctx, store.SessionUIDResolver, string(uid))\n      // ⚠️ missing: s.store.Options().InNamespace(tenant)\n      ...\n  }\n  ```\n\nThe `Authorize` middleware only verifies presence of a tenant in the context, not ownership of the requested session.\n\n## Proof of concept\n\nPre-requisite: attacker has any valid user account and has obtained a session UID from the victim tenant (UIDs may leak via logs, shared session recordings, UI URLs, or through the device IDOR in the companion advisory since sessions reference devices by UID).\n\n  ```bash\n  ATTACKER_TOKEN=$(curl -s -X POST http://target/api/login \\\n    -H 'Content-Type: application/json' \\\n    -d '{\"username\":\"attacker\",\"password\":\"...\"}' | jq -r .token)\n\n  # Attempt cross-tenant read\n  curl -i \"http://target/api/sessions/<victim-session-uid>\" \\\n    -H \"Authorization: Bearer $ATTACKER_TOKEN\"\n  # Expected (fixed):   HTTP 403/404\n  # Observed (v0.24.1): HTTP 200 + full session JSON\n  ```\n\n## Impact\n  - Cross-tenant disclosure of SSH session data: target username, device UID, remote IP, authenticated status, session type, terminal, position (geolocation), started_at / last_seen timestamps.\n  - Enables reconnaissance of other tenants' active users and systems; combined with session recording features, can enable deeper recon.\n\n## Suggested fix\n`api/services/session.go` — apply `InNamespace` in `GetSession`:\n\n  ```go\n  func (s *service) GetSession(ctx context.Context, uid models.UID) (*models.Session, error) {\n      tenant := gateway.TenantFromContext(ctx)\n      opts := []store.QueryOption{}\n      if tenant != nil {\n          opts = append(opts, s.store.Options().InNamespace(tenant.ID))\n      }\n      session, err := s.store.SessionResolve(ctx, store.SessionUIDResolver, string(uid), opts...)\n      ...\n  }\n  ```",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/shellhub-io/shellhub"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.24.2"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.24.1"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/shellhub-io/shellhub/security/advisories/GHSA-9w9c-9w8m-w89q"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-44423"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/shellhub-io/shellhub"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-639" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-06T23:22:39Z",
    "nvd_published_at" : "2026-05-13T22:16:44Z"
  }
}