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Fencer Vulns
medium 6.5

CVE-2021-43847 json

Authorization Bypass in Space Invite in HumHub

published 2021-12-20 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-30717

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.2%
EPSS 1.2% chance of exploitation in 30 days, percentile 68%
public exploits
0
none known

Summary

HumHub is an open-source social network kit written in PHP. Prior to HumHub version 1.10.3 or 1.9.3, it could be possible for registered users to become unauthorized members of private Spaces. Versions 1.10.3 and 1.9.3 contain a patch for this issue.

Patch / fix

  • humhub humhub 1.9.3, 1.10.3

Exploit prediction

1.22% chance of exploitation in the next 30 days, higher than 68% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • huntr.dev https://huntr.dev/bounties/943dad83-f0ed-4c74-ba81-7dfce7ca0ef2/ referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/humhub/humhub/security/advisories/GHSA-f5hc-5wfr-7v74 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 4.0 AV:N/AC:L/Au:S/C:P/I:N/A:N

Affected products

  • humhub humhub

Classification

Weakness

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.