CVE-2026-57569

Lychee is a free, open-source photo-management tool. Prior to 7.6.0, the POST /api/v2/Photo::fromUrl flow validates a hostname and its resolved addresses in app/Rules/PhotoUrlRule.php but later passes the original hostname through app/Actions/Import/FromUrl.php to app/Image/Files/DownloadedFile.php for a separate fopen connection. An authenticated attacker who controls DNS responses can cause validation to observe a public address and the subsequent fetch to resolve the same hostname to a private or otherwise forbidden address. This DNS rebinding time-of-check to time-of-use mismatch bypasses the intended server-side request forgery protections and can reach services available from the Lychee server, subject to deployment and TLS behavior. This issue is fixed in version 7.6.0.

• https://github.com/LycheeOrg/Lychee/commit/a5f23e314f1a933d31aa650616bf9cd84bd0407e
• https://github.com/LycheeOrg/Lychee/pull/4344
• https://github.com/LycheeOrg/Lychee/releases/tag/v7.6.0
• https://github.com/LycheeOrg/Lychee/security/advisories/GHSA-vj35-v9x5-vrxh
• https://github.com/LycheeOrg/Lychee/security/advisories/GHSA-vj35-v9x5-vrxh