{"id":"GHSA-ccfq-2454-f5xw","summary":"SillyTavern has a SSRF vulnerability in the CORS proxy middleware","details":"## Resolution\n\nSillyTavern 1.18.0 added a generic server-side request filter (Private Request Whitelisting). Since we expect users to use the application in a trusted environment, the filter is disabled by default, however it is strongly advised to be enabled and properly configured when an instance is being hosted over a network, as suggested by a console warning message and an officially published security checklist for administrators.\n\nDocumentation: \n\n- https://docs.sillytavern.app/administration/config-yaml/#private-address-whitelisting\n- https://docs.sillytavern.app/administration/#security-checklist\n\n## Note on future SSRF findings\n\nSince the request filter applies to the entire application, no SSRF vulnerabilities against individual endpoints will be accepted, unless it has been proven that a properly configured and enabled filter can be bypassed in an undocumented way. Only advisories disclosed before the 1.18.0 release will be posted if their concern is SSRF.\n\n## Overview\n- Vulnerability Type: SSRF\n- Affected Location: `src/middleware/corsProxy.js:31`\n- Trigger Scenario: SSRF in optional CORS proxy\n\n## Root Cause\n`corsProxyMiddleware` forwards `req.params.url` directly into `fetch(url, ...)`. It only blocks circular requests to its own host and does not enforce destination allowlist or private/loopback restrictions, enabling SSRF.\n\n## Source-to-Sink Chain\n1. Source (user-controlled input)\n- Entry point: `GET /proxy/:url(*)`\n\n2. Data flow\n- Code analysis shows concrete propagation into this sink:\n  - vulnerability title: `SSRF in optional CORS proxy`\n  - sink location reached by attacker-controlled input: `src/middleware/corsProxy.js:31`\n- The same sink behavior is confirmed by controlled execution observations.\n\n3. Sink (dangerous operation)\n- Sink location: `src/middleware/corsProxy.js:31`\n- Vulnerable behavior: SSRF in optional CORS proxy\n\n## Exploitation Preconditions\n1. The attacker can control or influence a URL/endpoint parameter.\n2. The server can access internal or sensitive network targets.\n3. Outbound request validation or redirect controls are insufficient.\n\n## Risk\nThis issue can be used to pivot network access and reach unintended internal resources.\n\n## Impact\nAn attacker may access internal network services or metadata endpoints and exfiltrate sensitive responses.\n\n## Remediation\n1. Enforce strict destination allowlist for proxy targets.\n2. Block loopback, link-local, RFC1918, and metadata address ranges.\n3. Apply the same destination validation to redirects.","aliases":["CVE-2026-44652"],"modified":"2026-06-09T10:45:15.637658527Z","published":"2026-05-12T22:24:05Z","database_specific":{"cwe_ids":["CWE-918"],"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2026-05-12T22:24:05Z","nvd_published_at":"2026-05-29T19:16:25Z"},"references":[{"type":"WEB","url":"https://github.com/SillyTavern/SillyTavern/security/advisories/GHSA-ccfq-2454-f5xw"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-44652"},{"type":"PACKAGE","url":"https://github.com/SillyTavern/SillyTavern"},{"type":"WEB","url":"https://github.com/SillyTavern/SillyTavern/releases/tag/1.18.0"}],"affected":[{"package":{"name":"sillytavern","ecosystem":"npm","purl":"pkg:npm/sillytavern"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.18.0"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-ccfq-2454-f5xw/GHSA-ccfq-2454-f5xw.json","last_known_affected_version_range":"\u003c= 1.17.0"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N"}]}