Cyber Resilience

CVE-2021-22895

MediumPublic PoC

Published: 11 June 2021

Published
11 June 2021
Modified
21 November 2024
KEV Added
—
Patch
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CVSS Score v3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
EPSS Score 0.0036 58.8th percentile
Risk Priority 12 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-22895 is a medium-severity Improper Certificate Validation (CWE-295) vulnerability in Debian Debian Linux. Its CVSS base score is 5.9 (Medium).

Operationally, ranked in the top 41.2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

Nextcloud Desktop Client before 3.3.1 is vulnerable to improper certificate validation due to lack of SSL certificate verification when using the "Register with a Provider" flow.

CWE(s)
CWE-295

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

nextcloud
desktop
≤ 3.1.3
debian
debian linux
10.0, 11.0

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

SA-19 Component Authenticity
addresses: CWE-295

When certificates are used to establish component provenance, the control requires correct certificate validation procedures.

SC-17 Public Key Infrastructure Certificates
addresses: CWE-295

Mandates approved trust anchors and issuance policies, directly preventing acceptance of unvalidated or untrusted certificates.

SC-45 System Time Synchronization
addresses: CWE-295

Correct system time is required for proper enforcement of certificate notBefore/notAfter dates and time-based revocation checks.

References