What is CVE-2026-33644?

CVE-2026-33644 is a medium-severity vulnerability in Lycheeorg Lychee, classified under Server-Side Request Forgery (SSRF). CVSS score: 4.3/10. Published 2026-03-26.

How severe is CVE-2026-33644?

Medium severity. CVSS v3 base score is 4.3 out of 10.

SSRF in Lycheeorg Lychee

CVE-2026-33644

Lychee is a free, open-source photo-management tool. Prior to version 7.5.2, the SSRF protection in `PhotoUrlRule.php` can be bypassed using DNS rebinding. The IP validation check (line 86-89) only activates when the hostname is an IP address. When a domain name is used, `filter_var($host, FILTER_VALIDATE_IP)` returns `false`, skipping the entire check. Version 7.5.2 patches the issue.

Vulnerability class: SSRF (Server-Side Request Forgery)

Published 2026-03-26 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.003 (20.3th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 20th percentile — 20.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001

Affected products

Lycheeorg Lychee — versions < 7.5.2

Weakness classification (CWE)

CWE-918 — Server-Side Request Forgery (SSRF)

References

github.com/LycheeOrg/Lychee/security/advisories/GHSA-5245-4p8c-jwff (Exploit, Vendor Advisory)
github.com/LycheeOrg/Lychee/commit/28c5261fb9deab4f9420c8cc2f73a87425939107 (Patch)

Frequently asked questions

What is CVE-2026-33644?: CVE-2026-33644 is a medium-severity vulnerability in Lycheeorg Lychee, classified under Server-Side Request Forgery (SSRF). CVSS score: 4.3/10. Published 2026-03-26.
How severe is CVE-2026-33644?: Medium severity. CVSS v3 base score is 4.3 out of 10.