CVE-2026-52841 — Easy!Appointments: Authorization bypass in Google OAuth provider binding lets any backend user rebind a peer provider's Google sync
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.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- No scoring signals.
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Alextselegidis Easyappointments).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Exploitation requires user interaction: tighten email/web filtering and warn affected users.
- Search available logs for exploit probes matching the vulnerability class (access control), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Alextselegidis | Easyappointments | version < 1.6.0 | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 3.1 | CVSS 3.1 | Low | 0.5 | 2.5 | security-advisories@github.com via NIST National Vulnerability Database |
| 3.1 | CVSS 3.1 | Low | — | — | GitHub_M via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:N (score shown at the top: security-advisories@github.com) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
CWE-639 · Authorization Bypass Through User-Controlled Key (IDOR)
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
- Audit administrative actions and access to resources outside each user’s normal pattern.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · alextselegidis/easyappointments
- SSVC assessment updated
- Record published
- CVSS changed · 3.1
- Source status changed · → Deferred
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
2 on the record
Elsewhere on this site
Related CVEs (same products)
- High CVE-2026-108758 Easy!Appointments through 1.6.0 Authorization Bypass via booking/register Endpoint 4d
- Low CVE-2026-52838 Easy!Appointments disable_booking_message rendered as raw HTML on public booking page — Stored XSS Jul 14, 2026
- Low CVE-2026-52839 Easy!Appointments appointments/store and appointments/update allow cross-provider appointment injection — Authorization Bypass Jul 14, 2026
- Low CVE-2026-52840 Easy!Appointments has server-side request forgery in CalDAV connection test that exposes the deployment's internal network Jul 14, 2026
- High CVE-2026-55651 Easy!Appointments Vulnerable to Appointments Takeover via Excessive Data Exposure Jul 14, 2026
- Medium CVE-2026-52837 Easy!Appointments has unauthenticated customer PII disclosure on booking reschedule page Jul 14, 2026
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No FIRST EPSS score.
- No fixed version, patch or mitigation documented.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-52841 is "Easy!Appointments: Authorization bypass in Google OAuth provider binding lets any backend user rebind a peer provider's Google sync", rated Low. It affects Easyappointments (Alextselegidis); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 3.1 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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