CVE-2026-33537Public exploitNetwork attack vector

Authenticated SSRF via incomplete direct-IP validation

Published Mar 26, 2026 · Updated Mar 26, 2026

SSRF in Lychee before 7.5.1 allows remote authenticated users to access internal HTTP services through Photo::fromUrl. PhotoUrlRule validates direct IP hosts with FILTER_FLAG_NO_PRIV_RANGE alone and compares only the literal localhost name, leaving loopback and link-local ranges allowed. Any authenticated account can bypass all four default protections to query local services or cloud instance metadata.

CVSS severity5.3
Medium
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in Lychee before 7.5.1 allows remote authenticated users to access internal HTTP services through Photo::fromUrl. PhotoUrlRule validates direct IP hosts with FILTER_FLAG_NO_PRIV_RANGE alone and compares only the literal localhost name, leaving loopback and link-local ranges allowed. Any authenticated account can bypass all four default protections to query local services or cloud instance metadata.

The record

CVE
CVE-2026-33537
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

  1. Mar 26, 2026CVE publishedPublication date reported by the CVE source.
  2. 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.

  1. Affected versionversion=< 7.5.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

LycheeOrg · Lycheeversion=< 7.5.1

Published CVSS scores

5.3GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N
6.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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