Booking Calendar <= 9.1 - PHP Object Injection via Shortcode
Noroxi assessment
Priority: Monitor (action score 36/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 1.7% (FIRST EPSS); higher than 77.2% of all records.
- Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
- According to the record, no fixed version is available yet.
Low priority for now. Update when a fix is released; follow the vendor's advisory.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
The Booking Calendar plugin for WordPress is vulnerable to PHP Object Injection via the [bookingflextimeline] shortcode in versions up to, and including, 9.1. This could be exploited by subscriber-level users and above to call arbitrary PHP objects on a vulnerable site.
- Published
- May 10, 2022
- Updated
- Jun 17, 2026
- EPSS
- 1.7% · 77th percentile
- CWE
- CWE-502
Report tools
Action score
36
Monitor
Low priority for now.
- CVSS
- 35 / 40 · 8.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 1.7%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 8.8
- CNA · Wordfence
- 8.8
- agree
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Is Booking Calendar on your site?
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| booking calendar project | booking calendar | cpe:2.3:a:booking_calendar_project:booking_calendar |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- booking calendar project booking calendarup to 9.1 inclusive
Versions reported by the vendor
Affected version ranges reported by the assigning authority (Wordfence). Independent of NVD's CPE analysis and usually ahead of it.
wpdevelop Booking Calendar
- 9.1 and later · up to and including 9.1affected
Same product
booking calendar project: all recordsOther highest-scoring records for the same primary product.
- CVE-2018-20556SQL injection vulnerability in Booking Calendar plugin 8.4.3 for WordPress allows remote attackers to execute arbitrary SQL commands via the41Plan
- CVE-2018-5673An issue was discovered in the booking-calendar plugin 2.1.7 for WordPress.35Monitor
- CVE-2023-36384WordPress Booking Calendar Contact Form Plugin <= 1.2.40 is vulnerable to Cross Site Scripting (XSS)24Monitor
Published before and after this one in the same product
- ← EarlierCVE-2018-5671Jan 12, 2018 · An issue was discovered in the booking-calendar plugin 2.1.7 for WordPress.19Monitor
- ← EarlierCVE-2018-5672Jan 12, 2018 · An issue was discovered in the booking-calendar plugin 2.1.7 for WordPress.19Monitor
- ← EarlierCVE-2021-25040Jan 3, 2022 · Booking Calendar < 8.9.2 - Reflected Cross-Site Scripting24Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-502 · Deserialization of Untrusted DataCVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Root cause
Data received over the network is deserialized into the language’s native object format without verifying its source. Code paths inside the object can be triggered during deserialization.
The bug in code
The whole CWE-502 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
payload = sock.recv(65536)
job = pickle.loads(payload)Fixed
payload = sock.recv(65536)
if not hmac.compare_digest(sign(payload), header_sig):
raise PermissionError("invalid signature")
job = JobSchema.validate(json.loads(payload))Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Change log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.