CVE-2026-9304Public exploitNetwork attack vector

Authenticated SSRF via unchecked redirect targets

Published May 23, 2026 · Updated May 23, 2026

SSRF in the Logo API in Cal.com Cal.diy 4.9.0 through 4.9.4 allows remote authenticated users to read internal HTTP responses. The validateUrlForSSRF check approves an initial public logoUrl, but route.ts then uses redirect-following fetch(), allowing a 301 or 302 response to retarget the request to loopback, private-network, or metadata endpoints. Organization or team logo-editing access is required; returned bytes are proxied through /api/logo, enabling internal-service reads without reported code execution.

CVSS severity5.0
Medium
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in the Logo API in Cal.com Cal.diy 4.9.0 through 4.9.4 allows remote authenticated users to read internal HTTP responses. The validateUrlForSSRF check approves an initial public logoUrl, but route.ts then uses redirect-following fetch(), allowing a 301 or 302 response to retarget the request to loopback, private-network, or metadata endpoints. Organization or team logo-editing access is required; returned bytes are proxied through /api/logo, enabling internal-service reads without reported code execution.

The record

CVE
CVE-2026-9304
Published
May 23, 2026
Updated
May 23, 2026
Vendor
Cal.com, Inc.
Product
Cal.diy
Classifications
CWE-918, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 23, 2026CVE publishedPublication date reported by the CVE source.
  2. May 23, 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=4.9.0
  2. Affected versionversion=4.9.1
  3. Affected versionversion=4.9.2
  4. Affected versionversion=4.9.3
  5. Affected versionversion=4.9.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Cal.com, Inc. · Cal.diyversion=4.9.0; version=4.9.1; version=4.9.2; version=4.9.3; version=4.9.4

Published CVSS scores

4.6VulDBAV:N/AC:H/Au:S/C:P/I:P/A:P
5.0VulDBCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
1.3VulDBCVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P

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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