CVE-2021-34715Network attack vector

Authenticated code execution via malicious upgrade archive

Published Aug 18, 2021 · Updated Nov 7, 2024

Improper upgrade-package verification in Cisco TelePresence VCS Expressway allows remote authenticated users to execute code as _nobody. The image verification function insufficiently validates a malicious archive uploaded through the administrative Upgrade page, allowing its contents to run on the underlying operating system. Administrative credentials and management-interface access are required; successful exploitation grants internal user privileges rather than root access.

CVSS severity4.7
Medium
EPSS probability1.06%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper upgrade-package verification in Cisco TelePresence VCS Expressway allows remote authenticated users to execute code as _nobody. The image verification function insufficiently validates a malicious archive uploaded through the administrative Upgrade page, allowing its contents to run on the underlying operating system. Administrative credentials and management-interface access are required; successful exploitation grants internal user privileges rather than root access.

The record

CVE
CVE-2021-34715
Published
Aug 18, 2021
Updated
Nov 7, 2024
Vendor
ClamAV
Product
Cisco TelePresence Video Communication Server (VCS) Expressway
Classifications
CWE-347
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Aug 18, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 7, 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=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

ClamAV · Cisco TelePresence Video Communication Server (VCS) Expresswayversion=n/a

Published CVSS scores

7.2NISTCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
4.7Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L/E:X/RL:X/RC:X
9.0NISTAV:N/AC:L/Au:S/C:C/I:C/A:C

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.

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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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature

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

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Your stack

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