How severe is CVE-2026-22551?

No CVSS score has been assigned to CVE-2026-22551 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-22551?

CVE-2026-22551 affects the following packages: @theia/ai-chat-ui (npm), @theia/ai-chat (npm), @theia/ai-claude-code (npm), @theia/ai-code-completion (npm), @theia/ai-core (npm), @theia/ai-editor (npm), @theia/ai-ide (npm). Ecosystems affected: npm.

How do I fix CVE-2026-22551?

Update @theia/ai-chat-ui to 1.71.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-22551 is resolved across your whole dependency graph.

How do I detect CVE-2026-22551 in my npm dependencies?

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

How do I mitigate CVE-2026-22551 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.

Is CVE-2026-22551 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-22551 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 is the EPSS score for CVE-2026-22551?

CVE-2026-22551 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 23th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-22551?

CVE-2026-22551 is classified as CWE-201 (CWE-201), CWE-829 (CWE-829). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-22551 published, and has it been updated?

CVE-2026-22551 was published on June 18, 2026 and was last updated on October 24, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2026-22551: @theia/ai-chat-ui

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-22551.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs23th percentile — riskier than 23% of all scored CVEsHighest risk

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

Real-World Exposure

7 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

7other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

@theia/ai-chat-uinpm

4Kdownloads / week

@theia/ai-chatnpm

4Kdownloads / week

@theia/ai-claude-codenpm

2Kdownloads / week

Description

In Eclipse Theia versions prior to 1.71.0, the AI chat rendered Markdown image tags from AI responses, triggering HTTP requests to arbitrary external URLs without restriction. Combined with prompt injection in a malicious workspace, an attacker could induce the AI agent to construct image URLs encoding sensitive information from the workspace or conversation context, exfiltrating it to attacker-controlled servers. The workspace trust enforcement introduced in v1.71.0 mitigates the documented attack chain by disabling AI features in untrusted workspaces.

Affected Packages

7 total 7 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@theia/ai-chat-ui`	all versions	1.71.0`npm install @theia/ai-chat-ui@1.71.0`
📦npm	`@theia/ai-chat`	all versions	1.71.0`npm install @theia/ai-chat@1.71.0`
📦npm	`@theia/ai-claude-code`	all versions	1.71.0`npm install @theia/ai-claude-code@1.71.0`
📦npm	`@theia/ai-code-completion`	all versions	1.71.0`npm install @theia/ai-code-completion@1.71.0`
📦npm	`@theia/ai-core`	all versions	1.71.0`npm install @theia/ai-core@1.71.0`
📦npm	`@theia/ai-editor`	all versions	1.71.0`npm install @theia/ai-editor@1.71.0`

Affected Products

1 product · 1 configurations

Application

theiaeclipse

< 1.71.0

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @theia/ai-chat-ui, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @theia/ai-chat-ui to 1.71.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-22551 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.

Frequently Asked Questions

In Eclipse Theia versions prior to 1.71.0, the AI chat rendered Markdown image tags from AI responses, triggering HTTP requests to arbitrary external URLs without restriction. Combined with prompt injection in a malicious workspace, an attacker could induce the AI agent to construct image URLs encoding sensitive information from the workspace or conversation context, exfiltrating it to attacker-controlled servers. The workspace trust enforcement introduced in v1.71.0 mitigates the documented attack chain by disabling AI features in untrusted workspaces.

O3 Security · Impact-Aware SCA

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CVE-2026-22551 — @theia/ai-chat-ui