CVE-2026-34526: SillyTavern: Incomplete IP validation in /api/search/visit allows SSRF via localhost and IPv6

Severity: medium (CVSS 5.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-04-02 · updated 2026-07-24
Weakness: CWE-918

Description

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.

Affected products

SillyTavern: before 1.17.0 — fixed in 1.17.0

How to fix

Upgrade to a fixed version: SillyTavern 1.17.0. Check the vendor advisory for mitigations.

References

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