SillyTavern: Pre-authentication denial of service via body parsing
Summary
SillyTavern versions 1.12.13 through 1.19.0 run the body-parser middleware before authentication and whitelist checks. An unauthenticated remote attacker can send large or compressed JSON or urlencoded request bodies of up to 500 MB, optionally in parallel. This exhausts memory and CPU and can make the instance unavailable.
Affected
- SillyTavern 1.12.13 through 1.19.0
Fixed in
Unknown.
Workaround
Unknown.
Exploitation
- CISA SSVC: proof-of-concept exploit code exists
- CISA SSVC: not automatable
- CISA SSVC: partial technical impact
Our recommendation
- Check whether SillyTavern is reachable from untrusted networks, for example through port forwarding, tunnels or reverse proxies
- Restrict access to trusted networks or place the instance behind authentication at the network level until a fixed version is confirmed
- Update to a fixed release as soon as the vendor publishes one
- Monitor resource usage and request volume for unusual spikes
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- VulnCheck advisory www.vulncheck.com
- SillyTavern GitHub repository github.com
- SillyTavern server-main.js at 1.19.0 github.com
- HackMD write-up on pre-auth body parser DoS hackmd.io
- OSV entry CVE-2026-108545 osv.dev
- Vulners CVE-2026-108545 vulners.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 1 Nov 2026, 16:42.
Original description (NVD)
SillyTavern 1.12.13 through 1.19.0 contains a denial of service vulnerability that allows unauthenticated remote attackers to exhaust resources because body-parser middleware runs before authentication and whitelist checks. Attackers can send large or compressed JSON or urlencoded bodies up to 500 MB, optionally in parallel, to exhaust memory and CPU and deny service.
NVD references (4)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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