CVE-2026-4993Public exploit

LiteLLM authentication bypass via literal master key

Published Mar 28, 2026 · Updated Mar 28, 2026

Hard-coded credentials in Weights & Biases OpenUI 0.0.0 and 1.0 allow local users to access the embedded LiteLLM proxy. backend/openui/config.py omits the f-string prefix when assigning LITELLM_MASTER_KEY, so every default deployment uses the literal master key sk-{SESSION_KEY}. Exploitation requires local access and the LiteLLM integration; the known key bypasses proxy authentication and exposes configured model details.

CVSS severity3.3
Low
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Hard-coded credentials in Weights & Biases OpenUI 0.0.0 and 1.0 allow local users to access the embedded LiteLLM proxy. backend/openui/config.py omits the f-string prefix when assigning LITELLM_MASTER_KEY, so every default deployment uses the literal master key sk-{SESSION_KEY}. Exploitation requires local access and the LiteLLM integration; the known key bypasses proxy authentication and exposes configured model details.

The record

CVE
CVE-2026-4993
Published
Mar 28, 2026
Updated
Mar 28, 2026
Vendor
Weights & Biases
Product
OpenUI
Classifications
CWE-798, CWE-259, T1078
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 28, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.0.0
  2. Affected versionversion=1.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Weights & Biases · OpenUIversion=0.0.0; version=1.0

Published CVSS scores

1.9VulDBCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P
3.3VulDBCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
1.7VulDBAV:L/AC:L/Au:S/C:P/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-798Use of Hard-coded Credentials
CWE-259Use of Hard-coded Password
T1078Valid Accounts

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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