CVE-2026-9303Public exploitNetwork attack vector

Unauthorized state changes via forged browser requests

Published May 23, 2026 · Updated May 23, 2026

Cross-site request forgery in Cal.com Cal.diy 4.9.0 through 4.9.4 allows remote attackers to perform unauthorized actions via forged requests. The published record does not identify the affected function, endpoint, request parameters, or missing validation operation. Exploitation requires an authenticated user to load attacker-controlled content, and the documented consequence is limited to low-integrity modification rather than disclosure or service interruption.

CVSS severityUnavailable
Unscored
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site request forgery in Cal.com Cal.diy 4.9.0 through 4.9.4 allows remote attackers to perform unauthorized actions via forged requests. The published record does not identify the affected function, endpoint, request parameters, or missing validation operation. Exploitation requires an authenticated user to load attacker-controlled content, and the documented consequence is limited to low-integrity modification rather than disclosure or service interruption.

The record

CVE
CVE-2026-9303
Published
May 23, 2026
Updated
May 23, 2026
Vendor
Cal.com, Inc.
Product
Cal.diy
Classifications
CWE-352, CWE-862
Attack vector
network
Privileges
unauthenticated

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

Compare your product and version with the public record. A matching version still requires validation against your environment.

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 privilegesunauthenticated

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

5.3VulDBCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P
5.0VulDBAV:N/AC:L/Au:N/C:N/I:P/A:N/E:POC/RL:ND/RC:UR
4.3VulDBCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N/E:P/RL:X/RC:R
4.3VulDBCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N/E:P/RL:X/RC:R

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-352Cross-Site Request Forgery
CWE-862Missing Authorization

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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