How severe is CVE-2026-44651?

No CVSS score has been assigned to CVE-2026-44651 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-44651?

CVE-2026-44651 affects the following packages: sillytavern (npm). Ecosystems affected: npm.

How do I fix CVE-2026-44651?

Update sillytavern to 1.18.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-44651 is resolved across your whole dependency graph.

How do I detect CVE-2026-44651 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for sillytavern, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-44651 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2026-44651?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-44651 can be triaged on real exposure rather than presence alone.

Is CVE-2026-44651 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-44651 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-44651?

CVE-2026-44651 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 36th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-44651?

CVE-2026-44651 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-44651 published, and has it been updated?

CVE-2026-44651 was published on May 29, 2026 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

CVE-2026-44651 — sillytavern

CVE-2026-44651 is a Cross-site Scripting (XSS) vulnerability in sillytavern. A fix is available for sillytavern — see the affected versions and patch details below.

SillyTavern: Reflected XSS vulnerability in the CORS proxy middleware

Also known asGHSA-xc4x-2452-5gc9

Published

May 29, 2026

Updated

Aug 12, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 24, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-44651.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs36th percentile — riskier than 36% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

0other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

sillytavernnpm

397downloads / week

Description

Resolution

Fixed in SillyTavern 1.18.0: a user-provided URL is no longer reflected in the HTTP response body.

Overview

Vulnerability Type: XSS
Affected Location: src/middleware/corsProxy.js:40
Trigger Scenario: reflected XSS in CORS proxy error response

Root Cause

When fetch(url) throws, the code sends: res.status(500).send('Error occurred while trying to proxy to: ' + url + ' ' + error). The url value is attacker-controlled (req.params.url) and is not HTML-escaped before rendering.

Source-to-Sink Chain

Source (user-controlled input)

Entry point: GET /proxy/:url(*)

Data flow

Code analysis shows concrete propagation into this sink:
- vulnerability title: Reflected XSS in CORS proxy error response
- sink location reached by attacker-controlled input: src/middleware/corsProxy.js:40
The same sink behavior is confirmed by controlled execution observations.

Sink (dangerous operation)

Sink location: src/middleware/corsProxy.js:40
Vulnerable behavior: reflected XSS in CORS proxy error response

Exploitation Preconditions

The attacker can inject controllable content into a rendered response.
The vulnerable rendering context does not apply strict output encoding/sanitization.
A victim user opens the affected page or response.

Risk

This issue enables script execution in the victim context and can compromise session or data integrity.

Impact

An attacker may run arbitrary JavaScript in the victim context, steal tokens, and manipulate user-visible behavior.

Remediation

Never concatenate raw user input into HTML error responses.
If URL echo is required, HTML-escape it or force plain-text output.
Re-enable/strengthen CSP to reduce reflected injection impact.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`sillytavern`	all versions	1.18.0`npm install sillytavern@1.18.0`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for sillytavern, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update sillytavern to 1.18.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-44651 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-44651 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2026-44651. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## Resolution Fixed in SillyTavern 1.18.0: a user-provided URL is no longer reflected in the HTTP response body. ## Overview - Vulnerability Type: XSS - Affected Location: `src/middleware/corsProxy.js:40` - Trigger Scenario: reflected XSS in CORS proxy error response ## Root Cause When `fetch(url)` throws, the code sends: `res.status(500).send('Error occurred while trying to proxy to: ' + url + ' ' + error)`. The `url` value is attacker-controlled (`req.params.url`) and is not HTML-escaped before rendering. ## Source-to-Sink Chain 1. Source (user-controlled input) - Entry point: `GET /prox

O3 Security · Impact-Aware SCA

Is CVE-2026-44651 in your dependencies?

O3 Security finds CVE-2026-44651 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

Scan my dependencies How O3 SCA works