Authenticated SSRF via hostname-only IP validation
Published Mar 26, 2026 · Updated Mar 26, 2026
Server-side request forgery in Lychee before 7.5.2 allows remote authenticated users to access internal HTTP services via photo URL imports. PhotoUrlRule validates private or reserved addresses only when the URL host is already an IP address, so a hostname that resolves internally bypasses the check. Any authenticated user can submit the import request; DNS rebinding makes the server request localhost, private-network, or metadata endpoints.
Summary
What happened
Server-side request forgery in Lychee before 7.5.2 allows remote authenticated users to access internal HTTP services via photo URL imports. PhotoUrlRule validates private or reserved addresses only when the URL host is already an IP address, so a hostname that resolves internally bypasses the check. Any authenticated user can submit the import request; DNS rebinding makes the server request localhost, private-network, or metadata endpoints.
The record
- CVE
- CVE-2026-33644
- Published
- Mar 26, 2026
- Updated
- Mar 26, 2026
- Vendor
- LycheeOrg
- Product
- Lychee
- Classifications
- CWE-918, T1190
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 26, 2026CVE publishedPublication date reported by the CVE source.
- Mar 26, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 7.5.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Upstream DNS-rebinding reproductionproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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