CVE-2022-21695Public exploitNetwork attack vector

Concealed chat messaging via omitted join event

Published Jan 18, 2022 · Updated Apr 23, 2025

Improper access control in OnionShare 2.3 through 2.4 allows remote attackers to send chat messages while hidden from participants. The Chat mode server accepts message events from a Socket.IO client that omits the join event, leaving the client absent from session.users and the participant list. Access to an existing chatroom is required through public mode or a known private key, and a modified client or manual request can post concealed messages.

CVSS severity5.3
Medium
EPSS probability0.86%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in OnionShare 2.3 through 2.4 allows remote attackers to send chat messages while hidden from participants. The Chat mode server accepts message events from a Socket.IO client that omits the join event, leaving the client absent from session.users and the participant list. Access to an existing chatroom is required through public mode or a known private key, and a modified client or manual request can post concealed messages.

The record

CVE
CVE-2022-21695
Published
Jan 18, 2022
Updated
Apr 23, 2025
Vendor
OnionShare
Product
OnionShare
Classifications
CWE-287, T1564
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 18, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 23, 2025Record 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=< 2.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OnionShare · OnionShareversion=< 2.5

Published CVSS scores

5.1GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
5.3NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
4.3GitHub Security AdvisoriesCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
5.0NIST National Vulnerability DatabaseAV:N/AC:L/Au:N/C:N/I:P/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-287Improper Authentication
T1564Hide Artifacts

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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