{"id":"CVE-2026-71250","aliases":["EUVD-2026-53323","GHSA-q8pq-98hq-mg7f"],"status":"published","title":"Firefly III - Webhook URL Validation Explicitly Allows Loopback and Is Bypassable via DNS Rebinding","description":"Firefly III's webhook URL validator (IsValidWebhookUrl.php) filters most private/reserved IPv4 ranges but contains an explicit early-return that allows any resolved address in 127.0.0.0/8, permitting an authenticated user (with webhooks enabled, which is off by default) to configure a webhook targeting loopback services on the server.","severity":{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00276,"percentile":0.20243,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-918"],"published":"2026-08-05T10:57:08Z","modified":"2026-10-28T02:30:40Z","products":[{"vendor":"firefly-iii","product":"firefly-iii"}],"references":[{"url":"https://github.com/firefly-iii/firefly-iii","tags":["third-party-advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-71250","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-q8pq-98hq-mg7f"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/71xxx/CVE-2026-71250.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-71250","title":"Firefly III - Webhook URL Validation Explicitly Allows Loopback and Is Bypassable via DNS Rebinding","description":"Firefly III's webhook URL validator (IsValidWebhookUrl.php) filters most private/reserved IPv4 ranges but contains an explicit early-return that allows any resolved address in 127.0.0.0/8, permitting an authenticated user (with webhooks enabled, which is off by default) to configure a webhook targeting loopback services on the server.","status":"published","published":"2026-08-05T10:57:08.628Z","modified":"2026-08-10T11:46:07.818Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T14:19:49.559463Z"}],"euvd":[{"id":"EUVD-2026-53323","description":"Firefly III's webhook URL validator (IsValidWebhookUrl.php) filters most private/reserved IPv4 ranges but contains an explicit early-return that allows any resolved address in 127.0.0.0/8, permitting an authenticated user (with webhooks enabled, which is off by default) to configure a webhook targeting loopback services on the server.","status":"published","published":"2026-08-05T10:57:08Z","modified":"2026-08-10T11:46:07Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T18:02:05.732685Z"}],"ghsa":[{"id":"GHSA-q8pq-98hq-mg7f","title":"Firefly III's webhook URL validator (IsValidWebhookUrl.php) filters most private/reserved IPv4...","description":"Firefly III's webhook URL validator (IsValidWebhookUrl.php) filters most private/reserved IPv4 ranges but contains an explicit early-return that allows any resolved address in 127.0.0.0/8, permitting an authenticated user (with webhooks enabled, which is off by default) to configure a webhook targeting loopback services on the server. Additionally, the validator resolves the target hostname once via gethostbyname() at validation time, but the actual outbound request (StandardWebhookSender.php, via Guzzle) re-resolves the hostname independently at send time, allowing a DNS-rebinding attacker to pass validation against a public IP and have the real request delivered to a private or internal address. The webhook response body is only written to a server-side debug log, not returned to the triggering user, so this is a blind SSRF primitive rather than one with direct response read-back.","status":"published","published":"2026-08-05T12:31:32Z","modified":"2026-08-05T12:31:41Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T15:10:06.632203Z"}],"nvd":[{"id":"CVE-2026-71250","description":"Firefly III's webhook URL validator (IsValidWebhookUrl.php) filters most private/reserved IPv4 ranges but contains an explicit early-return that allows any resolved address in 127.0.0.0/8, permitting an authenticated user (with webhooks enabled, which is off by default) to configure a webhook targeting loopback services on the server.","status":"published","published":"2026-08-05T11:16:28.11Z","modified":"2026-08-26T17:13:24.8Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T14:12:35.031043Z"}],"osv":[{"id":"CVE-2026-71250","title":"Firefly III - Webhook URL Validation Explicitly Allows Loopback and Is Bypassable via DNS Rebinding","description":"Firefly III's webhook URL validator (IsValidWebhookUrl.php) filters most private/reserved IPv4 ranges but contains an explicit early-return that allows any resolved address in 127.0.0.0/8, permitting an authenticated user (with webhooks enabled, which is off by default) to configure a webhook targeting loopback services on the server.","status":"published","published":"2026-08-05T10:57:08.628Z","modified":"2026-10-28T02:30:40.7072543Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T15:45:15.164658Z"}]}}