Vulnerability-Lookup

CVE-2026-62283 (GCVE-0-2026-62283)

Vulnerability from cvelistv5 – Published: 2026-08-21 20:21 – Updated: 2026-08-21 21:42

Title

Nezha Monitoring: Cross-tenant terminal/file-manager session hijack via WebSocket stream UUID without ownership check

Summary

Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. Nezha versions 1.14.13 through 1.14.14 and 2.0.0 through 2.0.9 do not bind stream identifiers created by CreateStream in service/rpc/io_stream.go to their creating user, and `GET /ws/terminal/:id` and `GET /ws/file/:id` only check whether the supplied UUID exists. An authenticated RoleMember who obtains a live stream UUID from logs, browser history, referer data, or telemetry can attach to another user's terminal or file-manager session, read and write target-server files, and execute shell commands. This issue is fixed in version 2.0.10.

Severity

9.9 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-21 20:59 UTC

CWE

CWE-639 - Authorization Bypass Through User-Controlled Key
CWE-862 - Missing Authorization

Assigner

GitHub_M mitre root

References

3 references

URL	Tags
https://github.com/nezhahq/nezha/security/advisor…	x_refsource_CONFIRM
https://github.com/nezhahq/nezha/commit/6661d6a7f…	x_refsource_MISC
https://github.com/nezhahq/nezha/releases/tag/v2.0.10	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
nezhahq	nezha	Affected: >= 1.14.13, <= 1.14.14 Affected: >= 2.0.0, < 2.0.10	guessed

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-62283

Vulnerability from fkie_nvd - Published: 2026-08-21 21:17 - Updated: 2026-08-21 22:16

Severity

9.9 (Critical) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/nezhahq/nezha/commit/6661d6a7fc1c269f55c7f4e775082ad23fbe0f54
	security-advisories@github.com	https://github.com/nezhahq/nezha/releases/tag/v2.0.10
	security-advisories@github.com	https://github.com/nezhahq/nezha/security/advisories/GHSA-q6xx-5vr8-p898

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "nezha",
          "vendor": "nezhahq",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 1.14.13, \u003c= 1.14.14"
            },
            {
              "status": "affected",
              "version": "\u003e= 2.0.0, \u003c 2.0.10"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
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    {
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    }
  ],
  "id": "CVE-2026-62283",
  "lastModified": "2026-08-21T22:16:41.700",
  "metrics": {
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        "cvssData": {
          "attackComplexity": "LOW",
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}

GHSA-Q6XX-5VR8-P898

Vulnerability from github – Published: 2026-06-26 22:31 – Updated: 2026-06-26 22:31

Summary

Nezha vulnerable to cross-tenant terminal/file-manager session hijack via WebSocket stream UUID without ownership check

Details

Summary

In nezha v1.14.13–v1.14.14 and v2.0.0–v2.0.9, the WebSocket endpoints GET /ws/terminal/:id and GET /ws/file/:id authenticate the caller only by the presence of a valid stream UUID, with no ownership check tying that UUID to the user who created the stream. Any authenticated dashboard user (including a RoleMember) who learns a live stream UUID can attach to the session and gain interactive shell access or full file-manager control on the target server — i.e. cross-tenant RCE.

This was silently fixed in commit 6661d6a (2026-05-18, shipped in v2.0.10). At submission time no public CVE/GHSA covers this fix, so operators of v1.14.x and pre-v2.0.10 v2.x deployments have no signal that they are running vulnerable code.

Details

Stream allocation — service/rpc/io_stream.go (v2.0.9):

func (s *NezhaHandler) CreateStream(streamId string) {
    s.ioStreamMutex.Lock()
    defer s.ioStreamMutex.Unlock()

    s.ioStreams[streamId] = &ioStreamContext{
        userIoConnectCh:  make(chan struct{}),
        agentIoConnectCh: make(chan struct{}),
    }
}

No creator is bound to the stream.

Stream attach — cmd/dashboard/controller/terminal.go (v2.0.9):

// @Router /ws/terminal/{id} [get]
func terminalStream(c *gin.Context) (any, error) {
    streamId := c.Param("id")
    if _, err := rpc.NezhaHandlerSingleton.GetStream(streamId); err != nil {
        return nil, err
    }
    defer rpc.NezhaHandlerSingleton.CloseStream(streamId)
    // ... WebSocket upgrade and bidirectional pipe ...
}

The only authorization check is GetStream(streamId) — "does this UUID exist in the in-memory map". getUid(c) is never compared against the user who called createTerminal. The same pattern is present in fmStream(c) in cmd/dashboard/controller/fm.go.

Where the UUID leaks:

createTerminal returns the UUID to the legitimate client, which then opens wss://<dashboard>/ws/terminal/<UUID>. As a URL path component the UUID is exposed via:

Reverse-proxy access logs (nginx, Caddy, Cloudflare).
Referer headers when the page embeds external resources or error reporters.
Browser history / bookmark sync.
Frontend telemetry (Sentry, Bugsnag) breadcrumbs that include the WebSocket URL.
Any shared-tenant or multi-operator log viewer.

Any authenticated user with access to one of these side channels can attach to a live session.

PoC

Deploy nezha v2.0.9. Add at least one server. Configure two accounts: admin (RoleAdmin, owns the server) and member (RoleMember, no access to that server).
As admin, open the web terminal for the server. The browser opens wss://<dashboard>/ws/terminal/<UUID>. Capture this UUID from the network inspector, server access log, or Referer header.
From a separate session logged in as member, open wss://<dashboard>/ws/terminal/<UUID> (same UUID). The member's WebSocket attaches to the same ioStreamContext because terminalStream only checks GetStream(streamId) — no ownership check.
The member can now read the admin's shell output and inject keystrokes, achieving shell-level RCE on the target server, with no visible signal to the legitimate session owner.

Same flow works against /ws/file/:id (file-manager hijack: arbitrary read/write on the target server's filesystem).

Impact

Severity: Critical. Interactive RCE on a server administered by another user, with no audit signal to the rightful session owner.
Attack complexity: Low. The attacker needs an authenticated dashboard account (which any RoleMember is) and one captured UUID from a side channel.
Confidentiality / Integrity / Availability: all High. /ws/file/:id exposes arbitrary read+write on the target filesystem; /ws/terminal/:id is a full shell.

This is the same impact tier as CVE-2026-46716 (cross-tenant cron RCE) and arguably worse, because the entry point is a passively-leaked URL rather than an authenticated POST — attackers do not need direct dashboard interaction once the UUID is leaked through logs or telemetry.

Fix reference

Already fixed in master by commit 6661d6a ("fix(rpc): bind io_stream sessions to creator to prevent terminal/fm hijack"):

CreateStream now accepts a creatorUserID uint64 and stores it on the ioStreamContext.
New IsStreamAuthorizedForUser(streamId, userID, isAdmin) helper.
terminalStream and fmStream call this helper before the WebSocket upgrade and before the defer CloseStream(streamId), so a rejected attempt does not tear down a legitimate stream.

Shipped in v2.0.10 (2026-05-19). The v1.14 line has not received a backport.

Why this advisory

The fix landed silently. The other May 17–21 fixes received public GHSAs (GHSA-99gv-2m7h-3hh9, GHSA-rxf6-wjh4-jfj6, GHSA-hvv7-hfrh-7gxj, GHSA-w4g9-mxgg-j532, GHSA-6x26-5727-rrm9, GHSA-4g6j-g789-rghm) covering cron RCE, AlertRule trigger, telemetry leak, notification SSRF, DDNS SSRF, and agent forge-results respectively — but none cover the terminal / file-manager session hijack. This advisory closes that gap so operators of v1.14.x and v2.0.0–v2.0.9 know to upgrade.

Recommended action

Publish this GHSA so v2.x operators below v2.0.10 see the alert in their dependency scanners.
Either backport 6661d6a to a v1.14.15 release, or mark the v1.14 line end-of-life in SECURITY.md so operators understand the support boundary.

Severity

9.9 (Critical)


                  
                    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/nezhahq/nezha"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.14.13"
            },
            {
              "last_affected": "1.14.14"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.0.9"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/nezhahq/nezha"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.0.0"
            },
            {
              "fixed": "2.0.10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-639",
      "CWE-862"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-26T22:31:41Z",
    "nvd_published_at": null,
    "severity": "CRITICAL"
  },
  "details": "### Summary\n\nIn nezha **v1.14.13\u2013v1.14.14** and **v2.0.0\u2013v2.0.9**, the WebSocket endpoints `GET /ws/terminal/:id` and `GET /ws/file/:id` authenticate the caller only by the presence of a valid stream UUID, with no ownership check tying that UUID to the user who created the stream. Any authenticated dashboard user (including a `RoleMember`) who learns a live stream UUID can attach to the session and gain interactive shell access or full file-manager control on the target server \u2014 i.e. cross-tenant RCE.\n\nThis was silently fixed in commit [`6661d6a`](https://github.com/nezhahq/nezha/commit/6661d6a7fc1c269f55c7f4e775082ad23fbe0f54) (2026-05-18, shipped in v2.0.10). At submission time no public CVE/GHSA covers this fix, so operators of v1.14.x and pre-v2.0.10 v2.x deployments have no signal that they are running vulnerable code.\n\n### Details\n\n**Stream allocation \u2014 `service/rpc/io_stream.go` (v2.0.9):**\n\n```go\nfunc (s *NezhaHandler) CreateStream(streamId string) {\n    s.ioStreamMutex.Lock()\n    defer s.ioStreamMutex.Unlock()\n\n    s.ioStreams[streamId] = \u0026ioStreamContext{\n        userIoConnectCh:  make(chan struct{}),\n        agentIoConnectCh: make(chan struct{}),\n    }\n}\n```\n\nNo creator is bound to the stream.\n\n**Stream attach \u2014 `cmd/dashboard/controller/terminal.go` (v2.0.9):**\n\n```go\n// @Router /ws/terminal/{id} [get]\nfunc terminalStream(c *gin.Context) (any, error) {\n    streamId := c.Param(\"id\")\n    if _, err := rpc.NezhaHandlerSingleton.GetStream(streamId); err != nil {\n        return nil, err\n    }\n    defer rpc.NezhaHandlerSingleton.CloseStream(streamId)\n    // ... WebSocket upgrade and bidirectional pipe ...\n}\n```\n\nThe only authorization check is `GetStream(streamId)` \u2014 \"does this UUID exist in the in-memory map\". `getUid(c)` is never compared against the user who called `createTerminal`. The same pattern is present in `fmStream(c)` in `cmd/dashboard/controller/fm.go`.\n\n**Where the UUID leaks:**\n\n`createTerminal` returns the UUID to the legitimate client, which then opens `wss://\u003cdashboard\u003e/ws/terminal/\u003cUUID\u003e`. As a URL path component the UUID is exposed via:\n\n- Reverse-proxy access logs (nginx, Caddy, Cloudflare).\n- Referer headers when the page embeds external resources or error reporters.\n- Browser history / bookmark sync.\n- Frontend telemetry (Sentry, Bugsnag) breadcrumbs that include the WebSocket URL.\n- Any shared-tenant or multi-operator log viewer.\n\nAny authenticated user with access to one of these side channels can attach to a live session.\n\n### PoC\n\n1. Deploy nezha v2.0.9. Add at least one server. Configure two accounts: `admin` (RoleAdmin, owns the server) and `member` (RoleMember, no access to that server).\n2. As `admin`, open the web terminal for the server. The browser opens `wss://\u003cdashboard\u003e/ws/terminal/\u003cUUID\u003e`. Capture this UUID from the network inspector, server access log, or `Referer` header.\n3. From a separate session logged in as `member`, open `wss://\u003cdashboard\u003e/ws/terminal/\u003cUUID\u003e` (same UUID). The member\u0027s WebSocket attaches to the same `ioStreamContext` because `terminalStream` only checks `GetStream(streamId)` \u2014 no ownership check.\n4. The member can now read the admin\u0027s shell output and inject keystrokes, achieving shell-level RCE on the target server, with no visible signal to the legitimate session owner.\n\nSame flow works against `/ws/file/:id` (file-manager hijack: arbitrary read/write on the target server\u0027s filesystem).\n\n### Impact\n\n- **Severity**: Critical. Interactive RCE on a server administered by another user, with no audit signal to the rightful session owner.\n- **Attack complexity**: Low. The attacker needs an authenticated dashboard account (which any `RoleMember` is) and one captured UUID from a side channel.\n- **Confidentiality / Integrity / Availability**: all High. `/ws/file/:id` exposes arbitrary read+write on the target filesystem; `/ws/terminal/:id` is a full shell.\n\nThis is the same impact tier as CVE-2026-46716 (cross-tenant cron RCE) and arguably worse, because the entry point is a passively-leaked URL rather than an authenticated POST \u2014 attackers do not need direct dashboard interaction once the UUID is leaked through logs or telemetry.\n\n### Fix reference\n\nAlready fixed in master by commit [`6661d6a`](https://github.com/nezhahq/nezha/commit/6661d6a7fc1c269f55c7f4e775082ad23fbe0f54) (\"fix(rpc): bind io_stream sessions to creator to prevent terminal/fm hijack\"):\n\n- `CreateStream` now accepts a `creatorUserID uint64` and stores it on the `ioStreamContext`.\n- New `IsStreamAuthorizedForUser(streamId, userID, isAdmin)` helper.\n- `terminalStream` and `fmStream` call this helper **before** the WebSocket upgrade and **before** the `defer CloseStream(streamId)`, so a rejected attempt does not tear down a legitimate stream.\n\nShipped in v2.0.10 (2026-05-19). The v1.14 line has not received a backport.\n\n### Why this advisory\n\nThe fix landed silently. The other May 17\u201321 fixes received public GHSAs (GHSA-99gv-2m7h-3hh9, GHSA-rxf6-wjh4-jfj6, GHSA-hvv7-hfrh-7gxj, GHSA-w4g9-mxgg-j532, GHSA-6x26-5727-rrm9, GHSA-4g6j-g789-rghm) covering cron RCE, AlertRule trigger, telemetry leak, notification SSRF, DDNS SSRF, and agent forge-results respectively \u2014 but none cover the terminal / file-manager session hijack. This advisory closes that gap so operators of v1.14.x and v2.0.0\u2013v2.0.9 know to upgrade.\n\n### Recommended action\n\n- Publish this GHSA so v2.x operators below v2.0.10 see the alert in their dependency scanners.\n- Either backport `6661d6a` to a v1.14.15 release, or mark the v1.14 line end-of-life in `SECURITY.md` so operators understand the support boundary.",
  "id": "GHSA-q6xx-5vr8-p898",
  "modified": "2026-06-26T22:31:41Z",
  "published": "2026-06-26T22:31:41Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/nezhahq/nezha/security/advisories/GHSA-q6xx-5vr8-p898"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/nezhahq/nezha"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Nezha vulnerable to cross-tenant terminal/file-manager session hijack via WebSocket stream UUID without ownership check"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

CVE-2026-62283 (GCVE-0-2026-62283)

FKIE_CVE-2026-62283

GHSA-Q6XX-5VR8-P898

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Fix reference

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Recommended action

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