CVE-2021-1418Network attack vector

Authenticated client termination via crafted XMPP messages

Published Mar 24, 2021 · Updated Nov 8, 2024

Improper message validation in Cisco Jabber allows remote authenticated users to terminate the client by sending crafted XMPP messages. The client improperly validates message content; Cisco maps the flaw to improper null termination but does not identify the affected parser or function. Exploitation requires an account on the XMPP server used by the target and message delivery to the client; phone-only and Team Messaging modes are not affected.

CVSS severity4.3
Medium
EPSS probability0.94%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Improper message validation in Cisco Jabber allows remote authenticated users to terminate the client by sending crafted XMPP messages. The client improperly validates message content; Cisco maps the flaw to improper null termination but does not identify the affected parser or function. Exploitation requires an account on the XMPP server used by the target and message delivery to the client; phone-only and Team Messaging modes are not affected.

The record

CVE
CVE-2021-1418
Published
Mar 24, 2021
Updated
Nov 8, 2024
Vendor
ClamAV
Product
Cisco Jabber
Classifications
CWE-170, T1489
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 24, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 8, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

ClamAV · Cisco Jabberversion=n/a

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
4.0NIST NVDAV:N/AC:L/Au:S/C:N/I:N/A:P
4.3CiscoCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-170Improper Null Termination
T1489Service Stop

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo