GHSA-7XR2-Q9VF-X4R5
Vulnerability from github – Published: 2026-03-26 21:49 – Updated: 2026-04-18 00:43Summary
The patch for CVE-2026-32013 introduced symlink resolution and workspace boundary enforcement for agents.files.get and agents.files.set. However, two other handlers in the same file (agents.create and agents.update) still use raw fs.appendFile on the IDENTITY.md file without any symlink containment check. An attacker who can place a symlink in the agent workspace can hijack the IDENTITY.md path to append attacker-controlled content to arbitrary files on the system.
Details
In src/gateway/server-methods/agents.ts, the agents.create handler constructs the identity path and appends agent metadata without verifying symlinks:
// agents.create — line 283-291
const identityPath = path.join(workspaceDir, DEFAULT_IDENTITY_FILENAME);
const lines = [
"",
`- Name: ${safeName}`,
...(emoji ? [`- Emoji: ${sanitizeIdentityLine(emoji)}`] : []),
...(avatar ? [`- Avatar: ${sanitizeIdentityLine(avatar)}`] : []),
"",
];
await fs.appendFile(identityPath, lines.join("\n"), "utf-8"); // ← NO SYMLINK CHECK
The agents.update handler has the same issue at line 348-349:
// agents.update — line 348-349
const identityPath = path.join(workspace, DEFAULT_IDENTITY_FILENAME);
await fs.appendFile(identityPath, `\n- Avatar: ${sanitizeIdentityLine(avatar)}\n`, "utf-8"); // ← NO SYMLINK CHECK
fs.appendFile follows symlinks by default. If the IDENTITY.md file in the workspace is a symlink pointing to a sensitive file (e.g., /etc/crontab, ~/.bashrc, or ~/.ssh/authorized_keys), calling agents.create will append the agent identity metadata to that file.
The ensureAgentWorkspace function (called at line 274 before the append) uses exclusive-create mode (flag: 'wx') for IDENTITY.md. If a symlink already exists at that path, the EEXIST error is silently caught, and the subsequent fs.appendFile follows the symlink.
Attack flow:
1. Attacker plants symlink: workspace/IDENTITY.md → /etc/crontab
2. ensureAgentWorkspace skips creation (EEXIST from symlink)
3. fs.appendFile follows symlink → writes to /etc/crontab
4. Attacker-controlled content (name, emoji, avatar) injected into crontab → RCE
PoC
Prerequisites: Docker and Python 3 installed.
Step 1: Build and start the test environment.
cd llm-enhance/cve-finding/RCE/CVE-2026-32013-identity-appendFile-variant-exp/
docker compose up -d --build
sleep 3
Step 2: Run the exploit.
python3 poc_exploit.py
This script:
1. Plants a symlink IDENTITY.md → /etc/target-file.txt inside the agent workspace
2. Calls the agents.create API endpoint via HTTP POST
3. Verifies that the agent identity metadata was appended to /etc/target-file.txt
Step 3: Run the control experiment.
python3 control-patched_realpath.py
Step 4: Cleanup.
docker compose down
Log of Evidence
Exploit output:
=== CVE-2026-32013 Variant: Symlink Traversal via IDENTITY.md appendFile ===
[*] Planting symlink: IDENTITY.md -> /etc/target-file.txt
[*] Symlink: lrwxrwxrwx 1 root root 20 /workspaces/evil-agent/IDENTITY.md -> /etc/target-file.txt
[*] Original /etc/target-file.txt: ORIGINAL_SENSITIVE_CONTENT
[*] Calling agents.create with name='evil-agent'...
[*] API response: {'ok': True, 'agentId': 'evil-agent', 'workspace': '/workspaces/evil-agent'}
[*] /etc/target-file.txt after exploit:
ORIGINAL_SENSITIVE_CONTENT
- Name: evil-agent
- Emoji: 💀
- Avatar: evil.png
[+] SUCCESS! Symlink traversal confirmed.
[+] fs.appendFile followed IDENTITY.md symlink and wrote to /etc/target-file.txt
[+] Attacker-controlled content injected into arbitrary file.
Control output:
=== CONTROL: Patched agents.create blocks symlink traversal ===
[*] Planting symlink: IDENTITY.md -> /etc/target-file.txt
[*] Original /etc/target-file.txt: ORIGINAL_SENSITIVE_CONTENT
[*] Calling PATCHED agents.create with name='safe-agent'...
[*] API response: {'ok': False, 'error': 'symlink_traversal_blocked', 'realPath': '/etc/target-file.txt'}
[*] /etc/target-file.txt after patched call: ORIGINAL_SENSITIVE_CONTENT
[+] CONTROL PASSED: Patched endpoint detected and blocked symlink traversal.
[+] /etc/target-file.txt remains unchanged.
Impact
An attacker who can plant a symlink in the agent workspace directory can use the agents.create or agents.update gateway API to append attacker-controlled content to arbitrary files on the system. If the target file is:
/etc/crontabor user crontab → Remote Code Execution~/.bashrcor~/.profile→ Persistent code execution on login~/.ssh/authorized_keys→ Unauthorized SSH access- Application configuration files → Service disruption
The attacker-controlled content includes the agent name (arbitrary string), emoji, and avatar fields, which are only lightly sanitized (whitespace normalization via sanitizeIdentityLine).
Affected products
- Ecosystem: npm
- Package name: openclaw
- Affected versions: <= 2026.2.22
- Patched versions: None
Occurrences
| Permalink | Description |
|---|---|
| https://github.com/openclaw/openclaw/blob/main/src/gateway/server-methods/agents.ts#L283-L291 | agents.create handler uses fs.appendFile on IDENTITY.md without symlink resolution or workspace boundary check. |
| https://github.com/openclaw/openclaw/blob/main/src/gateway/server-methods/agents.ts#L348-L349 | agents.update handler uses fs.appendFile on IDENTITY.md without symlink resolution or workspace boundary check. |
| https://github.com/openclaw/openclaw/blob/main/src/gateway/server-methods/agents.ts#L274 | ensureAgentWorkspace is called before append, but its exclusive-create (wx) flag silently skips existing symlinks (EEXIST). |
{
"affected": [
{
"package": {
"ecosystem": "npm",
"name": "openclaw"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"last_affected": "2026.2.22"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-35632"
],
"database_specific": {
"cwe_ids": [
"CWE-61"
],
"github_reviewed": true,
"github_reviewed_at": "2026-03-26T21:49:25Z",
"nvd_published_at": null,
"severity": "MODERATE"
},
"details": "### Summary\n\nThe patch for CVE-2026-32013 introduced symlink resolution and workspace boundary enforcement for `agents.files.get` and `agents.files.set`. However, two other handlers in the same file (`agents.create` and `agents.update`) still use raw `fs.appendFile` on the `IDENTITY.md` file **without any symlink containment check**. An attacker who can place a symlink in the agent workspace can hijack the `IDENTITY.md` path to append attacker-controlled content to arbitrary files on the system.\n\n### Details\n\nIn `src/gateway/server-methods/agents.ts`, the `agents.create` handler constructs the identity path and appends agent metadata without verifying symlinks:\n\n```typescript\n// agents.create \u2014 line 283-291\nconst identityPath = path.join(workspaceDir, DEFAULT_IDENTITY_FILENAME);\nconst lines = [\n \"\",\n `- Name: ${safeName}`,\n ...(emoji ? [`- Emoji: ${sanitizeIdentityLine(emoji)}`] : []),\n ...(avatar ? [`- Avatar: ${sanitizeIdentityLine(avatar)}`] : []),\n \"\",\n];\nawait fs.appendFile(identityPath, lines.join(\"\\n\"), \"utf-8\"); // \u2190 NO SYMLINK CHECK\n```\n\nThe `agents.update` handler has the same issue at line 348-349:\n\n```typescript\n// agents.update \u2014 line 348-349\nconst identityPath = path.join(workspace, DEFAULT_IDENTITY_FILENAME);\nawait fs.appendFile(identityPath, `\\n- Avatar: ${sanitizeIdentityLine(avatar)}\\n`, \"utf-8\"); // \u2190 NO SYMLINK CHECK\n```\n\n`fs.appendFile` follows symlinks by default. If the `IDENTITY.md` file in the workspace is a symlink pointing to a sensitive file (e.g., `/etc/crontab`, `~/.bashrc`, or `~/.ssh/authorized_keys`), calling `agents.create` will append the agent identity metadata to that file.\n\nThe `ensureAgentWorkspace` function (called at line 274 before the append) uses exclusive-create mode (`flag: \u0027wx\u0027`) for `IDENTITY.md`. If a symlink already exists at that path, the `EEXIST` error is silently caught, and the subsequent `fs.appendFile` follows the symlink.\n\n**Attack flow:**\n```\n1. Attacker plants symlink: workspace/IDENTITY.md \u2192 /etc/crontab\n2. ensureAgentWorkspace skips creation (EEXIST from symlink)\n3. fs.appendFile follows symlink \u2192 writes to /etc/crontab\n4. Attacker-controlled content (name, emoji, avatar) injected into crontab \u2192 RCE\n```\n\n### PoC\n\n**Prerequisites:** Docker and Python 3 installed.\n\n**Step 1: Build and start the test environment.**\n```bash\ncd llm-enhance/cve-finding/RCE/CVE-2026-32013-identity-appendFile-variant-exp/\ndocker compose up -d --build\nsleep 3\n```\n\n**Step 2: Run the exploit.**\n```bash\npython3 poc_exploit.py\n```\n\nThis script:\n1. Plants a symlink `IDENTITY.md \u2192 /etc/target-file.txt` inside the agent workspace\n2. Calls the `agents.create` API endpoint via HTTP POST\n3. Verifies that the agent identity metadata was appended to `/etc/target-file.txt`\n\n**Step 3: Run the control experiment.**\n```bash\npython3 control-patched_realpath.py\n```\n\n**Step 4: Cleanup.**\n```bash\ndocker compose down\n```\n\n### Log of Evidence\n\n**Exploit output:**\n```\n=== CVE-2026-32013 Variant: Symlink Traversal via IDENTITY.md appendFile ===\n[*] Planting symlink: IDENTITY.md -\u003e /etc/target-file.txt\n[*] Symlink: lrwxrwxrwx 1 root root 20 /workspaces/evil-agent/IDENTITY.md -\u003e /etc/target-file.txt\n[*] Original /etc/target-file.txt: ORIGINAL_SENSITIVE_CONTENT\n\n[*] Calling agents.create with name=\u0027evil-agent\u0027...\n[*] API response: {\u0027ok\u0027: True, \u0027agentId\u0027: \u0027evil-agent\u0027, \u0027workspace\u0027: \u0027/workspaces/evil-agent\u0027}\n\n[*] /etc/target-file.txt after exploit:\n ORIGINAL_SENSITIVE_CONTENT\n\n- Name: evil-agent\n- Emoji: \ud83d\udc80\n- Avatar: evil.png\n\n[+] SUCCESS! Symlink traversal confirmed.\n[+] fs.appendFile followed IDENTITY.md symlink and wrote to /etc/target-file.txt\n[+] Attacker-controlled content injected into arbitrary file.\n```\n\n**Control output:**\n```\n=== CONTROL: Patched agents.create blocks symlink traversal ===\n[*] Planting symlink: IDENTITY.md -\u003e /etc/target-file.txt\n[*] Original /etc/target-file.txt: ORIGINAL_SENSITIVE_CONTENT\n\n[*] Calling PATCHED agents.create with name=\u0027safe-agent\u0027...\n[*] API response: {\u0027ok\u0027: False, \u0027error\u0027: \u0027symlink_traversal_blocked\u0027, \u0027realPath\u0027: \u0027/etc/target-file.txt\u0027}\n\n[*] /etc/target-file.txt after patched call: ORIGINAL_SENSITIVE_CONTENT\n\n[+] CONTROL PASSED: Patched endpoint detected and blocked symlink traversal.\n[+] /etc/target-file.txt remains unchanged.\n```\n\n### Impact\n\nAn attacker who can plant a symlink in the agent workspace directory can use the `agents.create` or `agents.update` gateway API to **append attacker-controlled content to arbitrary files** on the system. If the target file is:\n\n- `/etc/crontab` or user crontab \u2192 **Remote Code Execution**\n- `~/.bashrc` or `~/.profile` \u2192 **Persistent code execution on login**\n- `~/.ssh/authorized_keys` \u2192 **Unauthorized SSH access**\n- Application configuration files \u2192 **Service disruption**\n\nThe attacker-controlled content includes the agent name (arbitrary string), emoji, and avatar fields, which are only lightly sanitized (whitespace normalization via `sanitizeIdentityLine`).\n\n### Affected products\n- **Ecosystem**: npm\n- **Package name**: openclaw\n- **Affected versions**: \u003c= 2026.2.22\n- **Patched versions**: None\n\n### Occurrences\n\n| Permalink | Description |\n| :--- | :--- |\n| [https://github.com/openclaw/openclaw/blob/main/src/gateway/server-methods/agents.ts#L283-L291](https://github.com/openclaw/openclaw/blob/main/src/gateway/server-methods/agents.ts#L283-L291) | `agents.create` handler uses `fs.appendFile` on `IDENTITY.md` without symlink resolution or workspace boundary check. |\n| [https://github.com/openclaw/openclaw/blob/main/src/gateway/server-methods/agents.ts#L348-L349](https://github.com/openclaw/openclaw/blob/main/src/gateway/server-methods/agents.ts#L348-L349) | `agents.update` handler uses `fs.appendFile` on `IDENTITY.md` without symlink resolution or workspace boundary check. |\n| [https://github.com/openclaw/openclaw/blob/main/src/gateway/server-methods/agents.ts#L274](https://github.com/openclaw/openclaw/blob/main/src/gateway/server-methods/agents.ts#L274) | `ensureAgentWorkspace` is called before append, but its exclusive-create (`wx`) flag silently skips existing symlinks (EEXIST). |",
"id": "GHSA-7xr2-q9vf-x4r5",
"modified": "2026-04-18T00:43:06Z",
"published": "2026-03-26T21:49:25Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/openclaw/openclaw/security/advisories/GHSA-7xr2-q9vf-x4r5"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-35632"
},
{
"type": "ADVISORY",
"url": "https://github.com/advisories/GHSA-fgvx-58p6-gjwc"
},
{
"type": "PACKAGE",
"url": "https://github.com/openclaw/openclaw"
},
{
"type": "WEB",
"url": "https://github.com/openclaw/openclaw/blob/main/src/gateway/server-methods/agents.ts#L274"
},
{
"type": "WEB",
"url": "https://github.com/openclaw/openclaw/blob/main/src/gateway/server-methods/agents.ts#L283-L291"
},
{
"type": "WEB",
"url": "https://github.com/openclaw/openclaw/blob/main/src/gateway/server-methods/agents.ts#L348-L349"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/openclaw-symlink-traversal-via-identity-md-appendfile-in-agents-create-update"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "OpenClaw: Symlink Traversal via IDENTITY.md appendFile in agents.create/update (Incomplete Fix for CVE-2026-32013)"
}
Sightings
| Author | Source | Type | Date |
|---|
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.