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Fencer Vulns
medium 6.1

CVE-2021-42841 json

Insta HMS before 12.4.10 is vulnerable to XSS because of improper validation of user-supplied input by multiple scripts.

published 2022-01-06 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-29796

cvss
6.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 59%
public exploits
0
none known

Summary

Insta HMS before 12.4.10 is vulnerable to XSS because of improper validation of user-supplied input by multiple scripts. A remote attacker could exploit this vulnerability via a crafted URL to execute script in a victim's Web browser within the security context of the hosting Web site, once the URL is clicked. An attacker could use this vulnerability to steal the victim's cookie-based authentication credentials.

Patch / fix

  • practo insta_hms 12.4.10

Exploit prediction

0.88% chance of exploitation in the next 30 days, higher than 59% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/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.