# Logseq plugin flaws chain to RCE

Published: 2026-06-09 · Severity: medium · Sectors: technology
Canonical: https://vorant.io/reports/9b29f9f9-9473-5907-b686-224fcd255c61/logseq-plugin-flaws-chain-to-rce

> Four vulnerabilities in Logseq allow malicious plugins or XSS to escape the sandbox and achieve remote code execution.

CERT Polska coordinated disclosure of four vulnerabilities in the Logseq note-taking application, all stemming from insufficient isolation between the Electron renderer process and privileged host capabilities. CVE-2026-9279 involves an IPC handler that passes user-supplied arguments to child_process.spawn with shell:true, allowing shell metacharacters to bypass a command allowlist and achieve arbitrary command execution. CVE-2026-47899 exposes an Electron preload API that lacks path validation, enabling arbitrary file read/write/delete. CVE-2026-47900 is a stored XSS triggered by an unsanitized plugin package.json name field rendered via innerHTML. CVE-2026-47901 allows sandboxed plugin iframes to inject HTML event-handler attributes into the host DOM, bypassing a disabled CSP to execute JavaScript in the privileged host context.

Exploitation of any of these requires an attacker to first obtain JavaScript execution in the renderer, typically via a malicious plugin or an XSS vector, after which the chain escalates to full host-level code execution, filesystem access, or a sandbox escape. Only version v0.10.15 was confirmed vulnerable, and the vendor has not addressed the sandbox escape issue (CVE-2026-47901) at time of publication. The report credits researcher Bartłomiej Dmitruk (striga.ai) for responsible disclosure through CERT Polska's coordinated vulnerability disclosure process.

## Mentioned in this report

- Vulnerabilities: CVE-2026-47899, CVE-2026-47900, CVE-2026-47901, CVE-2026-9279

## Detection guidance (public sample)

### Logseq Electron Process Spawning Command Shell Interpreter

ATT&CK: T1059

Detects Logseq spawning cmd.exe, powershell.exe, sh or bash as a child process, consistent with exploitation of the child_process.spawn(shell:true) IPC handler flaw (CVE-2026-9279). Auto-generated starting point — validate and tune in your environment before deploying. IOC matches can false-positive on shared infrastructure and decay as adversary infrastructure rotates.

```yaml
title: Logseq Spawning Shell Interpreter Child Process
id: 247666b5-30ef-510a-938a-c26a82a04322
status: experimental
description: Detects Logseq (Electron note-taking app) launching a command interpreter
  as a child process, which is atypical for normal note-taking/plugin operation and
  consistent with exploitation of an IPC handler that passes user input to child_process.spawn
  with shell:true (CVE-2026-9279).
references:
- CERT Polska coordinated disclosure - Logseq plugin RCE chain
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    ParentImage|endswith:
    - \Logseq.exe
    - \logseq.exe
    Image|endswith:
    - \cmd.exe
    - \powershell.exe
    - \pwsh.exe
    - \wscript.exe
    - \cscript.exe
    - \sh.exe
    - \bash.exe
  filter:
    CommandLine|contains:
    - --version
    - --help
  condition: selection and not filter
falsepositives:
- Legitimate Logseq plugins that intentionally shell out to git or pandoc for document
  conversion
- Developer debugging sessions launching a shell from Logseq's dev tools
level: high
tags:
- attack.t1059
- attack.t1189
author: Vorant
```

### Logseq Child Process Command Line Containing Shell Metacharacters

ATT&CK: T1027

Detects shell metacharacters (chaining, substitution, backticks) in command lines of processes spawned by Logseq, indicative of allowlist bypass in the IPC command execution handler (CVE-2026-9279). Auto-generated starting point — validate and tune in your environment before deploying. IOC matches can false-positive on shared infrastructure and decay as adversary infrastructure rotates.

```yaml
title: Shell Metacharacter Command Injection From Logseq Child Process
id: eca8daa2-e2bb-5a0a-af86-b022552a88ee
status: experimental
description: Detects command lines launched by processes spawned from Logseq that
  contain shell metacharacters (;, |, &, $(), backticks) used to escape a command
  allowlist when Logseq passes user-supplied plugin/IPC arguments to child_process.spawn
  with shell:true (CVE-2026-9279).
references:
- CERT Polska coordinated disclosure - Logseq plugin RCE chain
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    ParentImage|endswith:
    - \Logseq.exe
    - \logseq.exe
  metachar:
    CommandLine|contains:
    - ;
    - '&&'
    - '||'
    - '|'
    - '`'
    - $(
    - '>%TEMP%'
  condition: selection and metachar
falsepositives:
- Legitimate plugin scripts that build multi-argument shell pipelines for file conversion
  utilities
level: high
tags:
- attack.t1027
- attack.t1059
author: Vorant
```

### Logseq Process Writing or Deleting Files Outside Plugin Data Directory

ATT&CK: T1055

Detects Logseq performing file write/delete operations to sensitive OS or user profile paths outside its own plugin/data directories, consistent with abuse of an unvalidated Electron preload file API (CVE-2026-47899). Auto-generated starting point — validate and tune in your environment before deploying. IOC matches can false-positive on shared infrastructure and decay as adversary infrastructure rotates.

```yaml
title: Logseq Arbitrary File Write Outside Application Directory
id: 1f47d9c1-155a-5619-a649-ff505a88b38d
status: experimental
description: Detects file write or delete events performed by the Logseq process targeting
  locations outside its expected application/plugin data directories (e.g. system
  folders, other users' profiles, startup folders), consistent with exploitation of
  an Electron preload API lacking path validation that allows arbitrary file read/write/delete
  (CVE-2026-47899).
references:
- CERT Polska coordinated disclosure - Logseq plugin RCE chain
logsource:
  category: file_event
  product: windows
detection:
  selection:
    Image|endswith:
    - \Logseq.exe
    - \logseq.exe
  suspicious_target:
    TargetFilename|contains:
    - \Windows\System32\
    - \Windows\SysWOW64\
    - \Startup\
    - \Users\Public\
    - \AppData\Roaming\Microsoft\Windows\Start Menu\
  filter:
    TargetFilename|contains:
    - \AppData\Roaming\Logseq\
    - \.logseq\
  condition: selection and suspicious_target and not filter
falsepositives:
- Logseq auto-update mechanism writing to legitimate application install paths
- Backup or sync plugins intentionally configured to write to shared public folders
level: medium
tags:
- attack.t1055
- attack.t1189
author: Vorant
```

Behavioural rules are generated from public reporting — validate in your environment before deploying.

Source reporting: https://cert.pl/en/posts/2026/06/CVE-2026-9279

---

This is the free public brief from Vorant Threat Intelligence. When citing, attribute "Vorant" and link https://vorant.io/reports/9b29f9f9-9473-5907-b686-224fcd255c61/logseq-plugin-flaws-chain-to-rce.
Full IOC sets, deployable detections, the entity graph, TAXII 2.1 feed and real-time alerts: https://vorant.io/signup