{"id":"CVE-2026-82639","title":"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","summary":"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 …","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","cwe":["CWE-20"],"published":"2026-08-30","updated":"2026-09-10","sourceUpdated":"2026-09-10T15:53:23.707","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-82639","references":[{"url":"https://github.com/ChatGPTNextWeb/NextChat","label":"disclosure@vulncheck.com"},{"url":"https://github.com/ChatGPTNextWeb/NextChat/blob/v2.16.1/app/api/proxy.ts","label":"disclosure@vulncheck.com"},{"url":"https://github.com/ChatGPTNextWeb/NextChat/issues/6814","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/nextchat-2.15.8-through-2.16.1-openai-api-key-disclosure","label":"disclosure@vulncheck.com"},{"url":"https://github.com/ChatGPTNextWeb/NextChat/issues/6814","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"tags":["nvd","cve.org","exploit-available"],"epss":0.00298,"epssPercentile":0.22715,"ingestedAt":"2026-08-30T23:59:28.088Z","vendor":"ChatGPTNextWeb","product":"NextChat","affected":["NextChat >= 2.15.8 <= 2.16.1"],"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"yes","technicalImpact":"partial","timestamp":"2026-08-31T16:51:12.882744Z"},"slug":"CVE-2026-82639","body":"## Overview\n\nNextChat 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":53,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":210230,"id":"CVE-2026-82639","ts":1790264815942,"field":"exploit_available","old":"false","new":"true"}]}