How severe is CVE-2026-49357?

No CVSS score has been assigned to CVE-2026-49357 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-49357?

CVE-2026-49357 affects the following packages: line-desktop-mcp (npm). Ecosystems affected: npm.

How do I fix CVE-2026-49357?

Update line-desktop-mcp to 1.1.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-49357 is resolved across your whole dependency graph.

How do I detect CVE-2026-49357 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for line-desktop-mcp. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2026-49357 if there is no patch (or I can't update yet)?

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.

How does O3 Security protect against CVE-2026-49357?

O3 pinpoints whether CVE-2026-49357 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2026-49357 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-49357 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What type of vulnerability is CVE-2026-49357?

CVE-2026-49357 is classified as Missing Authentication (CWE-306), CWE-862 (CWE-862). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-49357 published, and has it been updated?

CVE-2026-49357 was published on June 19, 2026 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

CVE-2026-49357

Fix: dtwang/line-desktop-mcp@6806178

CVE-2026-49357 is a Missing Authentication vulnerability in line-desktop-mcp. O3 Security confirms whether CVE-2026-49357 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

Streamable HTTP mode exposes LINE Desktop read/send tools without MCP authentication

Also known asGHSA-4hf8-5mjm-rfgq

Published

Jun 19, 2026

Updated

Aug 12, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Aug 12, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.

line-desktop-mcpnpm

37downloads / week

Description

Line Desktop MCP is a project that, while unaffiliated with the official line-bot-mcp-server, allows users to directly operate the LINE Desktop application on Windows or Mac via MCP. line-desktop-mcp supports a --http-mode Streamable HTTP transport for use with clients such as n8n. In this mode the server binds to 0.0.0.0 and exposes the MCP /mcp endpoint without an MCP-layer authentication check. Prior to version 1.1.2, any network client that can reach the port can initialize a session, list tools, and call tools that read LINE Desktop chat history or send LINE messages through the already logged-in desktop application. Version 1.1.2 fixes the issue.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`line-desktop-mcp`	all versions	1.1.2

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for line-desktop-mcp. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update line-desktop-mcp to 1.1.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-49357 is resolved across your whole dependency graph.
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.
How O3 protects you
O3 pinpoints whether CVE-2026-49357 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2026-49357. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Line Desktop MCP is a project that, while unaffiliated with the official line-bot-mcp-server, allows users to directly operate the LINE Desktop application on Windows or Mac via MCP. `line-desktop-mcp` supports a `--http-mode` Streamable HTTP transport for use with clients such as n8n. In this mode the server binds to `0.0.0.0` and exposes the MCP `/mcp` endpoint without an MCP-layer authentication check. Prior to version 1.1.2, any network client that can reach the port can initialize a session, list tools, and call tools that read LINE Desktop chat history or send LINE messages through the a

O3 Security · Impact-Aware SCA

Is CVE-2026-49357 in your dependencies?

O3 detects CVE-2026-49357 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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