8.1

CVE-2026-12378: unknown appointment booking calendar plugin and scheduling plugin Deserialization of Untrusted Data

CVSS: 8.1v3.1HighDeferred
Published 08-07-2026Last modified 08-07-2026
Open JSON

Vulnerability summary

CVE-2026-12378 is a high (CVSS 8.1) Deserialization of Untrusted Data vulnerability in unknown appointment booking calendar plugin and scheduling plugin. EPSS estimates a 0.65% chance of exploitation in the next 30 days, higher than 50.2% of scored vulnerabilities. 1 public exploit is recorded. Fixed in 1.5.6.

Overall risk
43/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.1/10
010
High · v3.1 (CVE.org)
EPSS score
0.65%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1reference

Timeline

  1. 08-07-2026
    PublishedVulnerability first disclosed.
  2. 08-07-2026
    Last modifiedVulnerability information updated.

Description

The Appointment Booking Calendar Plugin and Scheduling Plugin WordPress plugin through 1.1.28 does not validate data before passing it to a PHP deserialization function, allowing unauthenticated attackers to inject arbitrary PHP objects; where a suitable gadget chain is present on the site this can be leveraged to achieve remote code execution.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.65%

Chance of exploitation in the next 30 days

Percentile

50%

Versus all other CVEs

30-day change

0.00 pp

From 0.65% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.65%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

1 found
  • referenceUnverified

    Exploit Reference (wpscan.com)

    Maturity: unknown

Weaknesses

CWE · root cause

Affected systems

Unknown1 product
Wordpress1 product
  • bookingpress-appointment-booking≤ 1.5.5 (fixed in 1.5.6)

2 vendors · 2 products

References

2 links