CVE-2026-45351 — open-webui
MEDIUMCVE-2026-45351 is a medium-severity (CVSS 6.5) Information Exposure vulnerability in open-webui. A fix is available for open-webui — see the affected versions and patch details below.
Open WebUI: Exposure of System Prompt to Regular User [Non-Admin]
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-45351.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-45351 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 379,842 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
open-webuiReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Summary
A regular user [non-admin] can view the system prompt of the model which is set by an admin.
Details
When a regular user [non-admin] logs into the application, a http://IP:8080/api/models? web request is initiated by the application and in response, it reveals the system prompt of available models set by admin on models pages in workspace affecting the confidentiality of application
Affected System
Open WebUI v0.6.40 "main" branch
Vulnerability Details and Advisory from OWASP
LLM07:2025 System Prompt Leakage - https://genai.owasp.org/llmrisk/llm072025-system-prompt-leakage/
PoC
1. Regular User [Non-Admin] login on Open WebUI application. 2. A series of web requests get generated by the application, and the http://IP:8080/api/models? is also gets generated by application . 3. The response of http://IP:8080/api/models? web request reveals the system prompt of all the available models which is set is by the admin on models pages in workspace. <img width="940" height="352" alt="system prompt leak" src="https://github.com/user-attachments/assets/bd2c76f1-398f-4bc8-a8b2-5e14a768c560" />
Web Request
GET /api/models? HTTP/1.1 Host: localhost:8080 sec-ch-ua-platform: "Linux" authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6IjdmYjUxMmFhLTBmMTAtNDRkZi1iOWY1LThmNDg2MWFhNWFmOCIsImV4cCI6MTc2NjU2MjE5OH0.yJpavBynKItPQv76SMGKK012JIf29PVUv9sjuCDuRGQ Accept-Language: en-US,en;q=0.9 sec-ch-ua: "Chromium";v="141", "Not?A_Brand";v="8" sec-ch-ua-mobile: ?0 User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36 Accept: application/json Content-Type: application/json Sec-Fetch-Site: same-origin Sec-Fetch-Mode: cors Sec-Fetch-Dest: empty Referer: http://localhost:8080/ Accept-Encoding: gzip, deflate, br Cookie: token=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6IjdmYjUxMmFhLTBmMTAtNDRkZi1iOWY1LThmNDg2MWFhNWFmOCIsImV4cCI6MTc2NjU2MjE5OH0.yJpavBynKItPQv76SMGKK012JIf29PVUv9sjuCDuRGQ Connection: keep-alive
Impact
1. System prompts can reveal the model instructions, providing an attackers with inside knowledge about the system capabilities and bypass restrictions. 2. Attacker can perform content manipulation affecting the input/output of the model.
Details from MITRE ATLAS
Discover LLM System Information - https://atlas.mitre.org/techniques/AML.T0069 Discover LLM System Information: System Instruction Keywords - https://atlas.mitre.org/techniques/AML.T0069.001 Discover LLM System Information: System Prompt - https://atlas.mitre.org/techniques/AML.T0069.002
Recommendation
1. The web response should not reveal system prompt and related internal/back-end details regarding the model to the regular user. 2. Only the model name and non-sensitive details should be revealed to regular user and internal/back-end details should not be disclosed.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | open-webui | all versions | 0.8.9pip install --upgrade 'open-webui==0.8.9' |
Affected Products
open webuiopenwebuiDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for open-webui, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update open-webui to 0.8.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-45351 is resolved across your whole dependency graph.
Workarounds
Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.
Frequently Asked Questions
Is CVE-2026-45351 in your dependencies?
Find it across PyPI, including transitive dependencies.