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Fencer Vulns
medium 4.7

CVE-2021-34715 json

Cisco Expressway Series and TelePresence Video Communication Server Image Verification Vulnerability

published 2021-08-18 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-21365

cvss
4.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 64%
public exploits
0
none known

Summary

A vulnerability in the image verification function of Cisco Expressway Series and Cisco TelePresence Video Communication Server (VCS) could allow an authenticated, remote attacker to execute code with internal user privileges on the underlying operating system. The vulnerability is due to insufficient validation of the content of upgrade packages. An attacker could exploit this vulnerability by uploading a malicious archive to the Upgrade page of the administrative web interface. A successful exploit could allow the attacker to execute code with user-level privileges (the _nobody account) on the underlying operating system.

Patch / fix

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

1.06% chance of exploitation in the next 30 days, higher than 64% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 4.7 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L
NVD 3.1 7.2 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 9.0 AV:N/AC:L/Au:S/C:C/I:C/A:C

Affected products

  • Cisco Cisco TelePresence Video Communication Server (VCS) Expressway

Classification

Weakness
  • CWE-347 Improper Verification of Cryptographic Signature

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.