High · CVSS 8.6CVE-2026-58497

Uni-CLI: Legacy HTTP MCP transport accepted browser-originated localhost requestsCVE-2026-58497

Answer in brief

CVE-2026-58497 records a High severity (CVSS 8.6) vulnerability in Uni-CLI: Legacy HTTP MCP transport accepted browser-originated localhost requests. The current sources do not mark it as known exploited. The current feed maps olo-dot-io/Uni-CLI (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 23, 2026Updated Oct 23, 2026Source checked Oct 23, 2026First seen by HOL Oct 23, 2026Material review Oct 23, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.6
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 8.6. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps olo-dot-io/Uni-CLI (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
olo-dot-io/Uni-CLIgeneric	<0.225.2	0.225.2

Recommended response

Check inventory. Check lockfiles and deployed manifests for olo-dot-io/Uni-CLI.
Review the reported fix. Update olo-dot-io/Uni-CLI to 0.225.2 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Oct 23, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 23, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 23, 2026

Sources and claim methodology

Upstream source description

Uni-CLI gives people and agents one command interface for websites, browsers, desktop applications, local tools, and MCP. Prior to version 0.225.2, Uni-CLI exposed the legacy JSON-RPC-over-HTTP MCP transport on loopback without validating browser Origin headers before routing requests. A malicious web page could send a CORS simple POST request, such as text/plain, to the local /mcp endpoint and deliver a JSON-RPC body to the dispatcher. If the user had started the local MCP HTTP transport, that page could drive tools/call requests against the user's local Uni-CLI server. The Streamable HTTP transport already enforced this browser-to-localhost boundary. The legacy stateless HTTP path did not, so the two HTTP transports had drifted. This issue is about the browser-to-localhost boundary; it does not change Uni-CLI's local-code-execution trust model. This issue has been patched in version 0.225.2.

Quoted source text, attributed separately from HOL analysis.