How severe is CVE-2021-43847?

CVE-2021-43847 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-43847 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (64th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43847?

CVE-2021-43847 affects Humhub. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-43847?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-43847 published?

CVE-2021-43847 was published on 2021-12-20 and last updated on 2026-06-17.

CVE-2021-43847

CVE-2021-43847 is a medium-severity vulnerability in Humhub with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-862.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.0
EPSS exploit prediction: 1% (64th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-862
Affected product: Humhub
Published: 2021-12-20
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2021-43847?: 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.
How severe is CVE-2021-43847?: CVE-2021-43847 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-43847 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (64th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43847?: CVE-2021-43847 affects Humhub. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-43847?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-43847 published?: CVE-2021-43847 was published on 2021-12-20 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:humhub:humhub:*:*:*:*:*:*:*:*

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CVE-2019-11564 — Medium (CVSS 6.1): A cross-site scripting (XSS) vulnerability in HumHub 1.3.12 allows remote attackers to inject arbitrary web script or…
CVE-2019-9094 — Medium (CVSS 6.1): A Reflected Cross Site Scripting (XSS) Vulnerability was discovered in /s/adada/cfiles/upload in Humhub 1.3.10…

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