EUVD-2026-68215
GHSA-87fx-h8m6-gxwv
Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Network-reachable, no privileges or interaction needed; only the server-held API key (confidentiality) is compromised, no integrity or availability impact.
Primary rating from Vendor (VulnCheck).
CVSS VectorVendor: VulnCheck
Lifecycle Timeline
2DescriptionCVE.org
NextChat versions from 2.15.8 through 2.16.1 contain an improper URL validation vulnerability in the proxy endpoint that allows attackers to obtain the server's OpenAI API key. The x-base-url header is validated using substring matching instead of hostname parsing, allowing any URL containing 'api.openai.com' to pass validation and receive the server's credentials in the Authorization header.
AnalysisAI
Credential exfiltration in NextChat 2.15.8-2.16.1 allows unauthenticated network attackers to steal the server's OpenAI API key by exploiting flawed URL validation in the proxy endpoint. The x-base-url header is checked using substring matching rather than hostname parsing, so any URL containing the string 'api.openai.com' - including attacker-controlled domains like 'evil.attacker.com/api.openai.com' - passes validation and causes NextChat to forward the OpenAI API key in the Authorization header to the attacker's server. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | The NextChat instance must have a server-side OpenAI API key configured (as opposed to requiring users to provide their own keys). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 score of 8.7 (AV:N/AC:L/AT:N/PR:N/UI:N) accurately reflects the severity: the attack is remotely executable, requires no privileges or user interaction, and yields high confidentiality impact through API key exfiltration. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | No vendor-released patch identified at time of analysis - the references point to the vulnerable source code at v2.16.1 with no mention of a fixed release. … Detailed patch versions, workarounds, and compensating controls in full report. |
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Same weakness CWE-20 – Improper Input Validation
View allSame technique Information Disclosure
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External POC / Exploit Code
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