Skip to content
Noroxi
CVE.org (no NVD analysis yet)· CNA Patchstack

CVE-2026-39601: WordPress Booking Calendar plugin <= 11.8.4 - Race Condition vulnerability

Noroxi assessment

Priority: Monitor (action score 14/100)

  • 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: 0.15% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: WPdevelop Booking Calendar 11.9.

Low priority for now. Upgrade to WPdevelop Booking Calendar 11.9 or later.

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

Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability in WPdevelop Booking Calendar booking allows Leveraging Race Conditions.This issue affects Booking Calendar: from n/a through 11.8.4.

LowCVSS 3.7 · v3.1—No exploit Fix available
Published
Oct 2, 2026
Updated
Oct 5, 2026
EPSS
0.1% · 4th percentile

Report tools

JSON

Action score

14

Monitor

Low priority for now.

CVSS
14 / 40 · 3.7 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Patchstack
3.7
NVD has not scored this yet; the score shown is the CNA’s.

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?

WP Lens reads your site's plugin, theme and WordPress versions from the outside and matches them to known vulnerabilities. Works without an account.

Follow CVE-2026-39601

Is Booking Calendar on your site?

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

Your free account also gets you

  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for wpdevelop records
If any of these changes, we'll tell you in the daily email digest.
Is your version affected? Check it

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 help

Affected 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.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Patchstack). Independent of NVD's CPE analysis and usually ahead of it.

  • WPdevelop Booking Calendar

    • up to and including 11.8.4affectedfixed in 11.9

Same product

wpdevelop: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-32358WordPress Booking Calendar plugin <= 10.14.15 - SQL Injection vulnerability
    30Monitor
  • CVE-2025-14383Booking Calendar <= 10.14.8 - Unauthenticated SQL Injection via dates_to_check
    30Monitor
  • CVE-2026-92619Booking Calendar <= 11.8.2 - Authenticated (Editor+) Privilege Escalation to 'data_name' Parameter
    28Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-92561Sep 18, 2026 · Booking Calendar <= 11.8.2 - Reflected Cross-Site Scripting via 'options' Parameter
    24Monitor
  • ← EarlierCVE-2026-93655Sep 22, 2026 · Booking Calendar <= 11.8.3 - Reflected Cross-Site Scripting via 'wpbc_auto_fill' Parameter
    24Monitor
  • Later →CVE-2026-18496Oct 10, 2026 · Booking Calendar <= 11.4.3 - Unauthenticated Sensitive Information Exposure in 'WPBC_FLEXTIMELINE_NAV' AJAX Action
    21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
WPdevelop Booking Calendar11.9Vendor (CNA)

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.

  1. Published
  2. Fix recorded+3 d
  3. TodayOct 27, 2026+24 d
EPSS, last 120 days

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 researchers

Finders, 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.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
none
Integrity
low · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-362 · Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓
  2. SSVC exploitation— → none
  3. Exploit maturity— → none

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records