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Fencer Intel
low 3.1

CVE-2026-52841 json

Easy!Appointments: Authorization bypass in Google OAuth provider binding lets any backend user rebind a peer provider's Google sync

published 3mo ago modified yesterday also EUVD-2026-43723 , GHSA-8hm4-r66f-29wr

cvss
3.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 10%
public exploits
0
none known

Summary

Easy!Appointments is a self hosted appointment scheduler. In versions prior to 1.6.0, `Google::oauth` at `application/controllers/Google.php:278` stores its URL-supplied `provider_id` in the session, and `oauth_callback` saves the issued Google OAuth token against that row without checking the caller owns the provider. Any logged-in backend user (admin, provider, or secretary) rebinds a peer provider's Google sync to a Google account they control. The peer's appointments then sync into the attacker's calendar with each customer's name and email attached as attendee data. Version 1.6.0 patches the issue.

Patch / fix

  • packagist alextselegidis/easyappointments 1.6.1
  • easyappointments easyappointments 1.6.0

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
3mo ago

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 10% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/alextselegidis/easyappointments/security/advisories/GHSA-8hm4-r66f-29wr referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 3.1 CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:N
GitHub 3.1 3.1 CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
packagist alextselegidis/easyappointments
<1.6.1
1.6.1

Affected products

  • alextselegidis easyappointments

Classification

Weakness
  • CWE-639 Authorization Bypass Through User-Controlled Key

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.