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Fencer Vulns
medium 5.4

CVE-2021-27564 json

A stored XSS issue exists in Appspace 6.2.4.

published 2021-02-22 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-14315

cvss
5.4
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits
0
none known

Summary

A stored XSS issue exists in Appspace 6.2.4. After a user is authenticated and enters an XSS payload under the groups section of the network tab, it is stored as the group name. Whenever another member visits that group, this payload executes.

Exploit prediction

0.54% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/viperbluff/Appspace-Ver-6.2.4-Stored-Xss referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/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.