CVE-2024-0855Public exploitNetwork attack vector

Contributor impersonation via unchecked event author

Published Feb 27, 2024 · Updated Aug 8, 2024

Incorrect authorization in Spiffy Calendar before 4.9.9 allows remote authenticated users to create events attributed to another user. The event-creation handler accepts a client-supplied event_author value without verifying that it matches the submitting account, then stores the chosen user ID as the event author. Contributor-level access and event-creation permission are required; a crafted request can make an event appear to have been created by an administrator.

CVSS severity5.3
Medium
EPSS probability0.48%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in Spiffy Calendar before 4.9.9 allows remote authenticated users to create events attributed to another user. The event-creation handler accepts a client-supplied event_author value without verifying that it matches the submitting account, then stores the chosen user ID as the event author. Contributor-level access and event-creation permission are required; a crafted request can make an event appear to have been created by an administrator.

The record

CVE
CVE-2024-0855
Published
Feb 27, 2024
Updated
Aug 8, 2024
Vendor
Spiffy Plugins
Product
Spiffy Calendar
Classifications
CWE-863, T1656
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 27, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 8, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <4.4.9
  2. Affected versionversion=0 <4.9.9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Spiffy Plugins · Spiffy Calendarversion=0 <4.4.9; version=0 <4.9.9

Published CVSS scores

5.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-863Incorrect Authorization
T1656Impersonation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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