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Fencer Vulns
medium 4.8

CVE-2021-34190 json

A stored cross site scripting (XSS) vulnerability in index.php?menu=billing_rates of Issabel PBX version 4 allows attackers to execute arbi…

published 2021-07-06 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-20852

cvss
4.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 50%
public exploits
0
none known

Summary

A stored cross site scripting (XSS) vulnerability in index.php?menu=billing_rates of Issabel PBX version 4 allows attackers to execute arbitrary web scripts or HTML via a crafted payload entered into the "Name" or "Prefix" fields under the "Create New Rate" module.

Exploit prediction

0.64% chance of exploitation in the next 30 days, higher than 50% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • research.0xdutra.com https://research.0xdutra.com/posts/research-issabel-stored-xss/ referenced PoC, tagged "exploit" by a source, unverified
  • youtube.com https://www.youtube.com/watch?v=apJH_D68lZI referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 4.8 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 3.5 AV:N/AC:M/Au:S/C:N/I:P/A:N

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

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.