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Fencer Vulns
medium 5.4

CVE-2021-26549 json

An XSS issue was discovered in SmartFoxServer 2.17.0.

published 2021-02-09 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-13348

cvss
5.4
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.4%
EPSS 1.4% chance of exploitation in 30 days, percentile 71%
public exploits
0
none known

Summary

An XSS issue was discovered in SmartFoxServer 2.17.0. Input passed to the AdminTool console is not properly sanitized before being returned to the user. This can be exploited to execute arbitrary HTML code in a user's browser session in context of an affected site.

Exploit prediction

1.36% chance of exploitation in the next 30 days, higher than 71% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • zeroscience.mk https://www.zeroscience.mk/en/vulnerabilities/ referenced PoC, tagged "exploit" by a source, unverified
  • packetstormsecurity.com http://packetstormsecurity.com/files/161335/SmartFoxServer-2X-2.17.0-God-Mode-Console-WebSocket-Cross-Site-Scripting.html referenced PoC, tagged "exploit" by a source, unverified
  • zeroscience.mk https://www.zeroscience.mk/en/vulnerabilities/ZSL-2021-5626.php 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.