Cyber Resilience

CVE-2021-42564

MediumPublic PoC

Published: 30 November 2021

Published
30 November 2021
Modified
21 November 2024
KEV Added
—
Patch
—
CVSS Score v3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
EPSS Score 0.0014 33.9th percentile
Risk Priority 11 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-42564 is a medium-severity Open Redirect (CWE-601) vulnerability in Cryptshare Cryptshare Server. Its CVSS base score is 5.4 (Medium).

Operationally, ranked at the 33.9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

An open redirect through HTML injection in confidential messages in Cryptshare before 5.1.0 allows remote attackers (with permission to provide confidential messages via Cryptshare) to redirect targeted victims to any URL via the '<meta http-equiv="refresh"' substring in the editor parameter.

CWE(s)
CWE-601

Related Threats

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

Affected Assets

cryptshare
cryptshare server
≤ 5.1.0

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.

AT-2 Literacy Training and Awareness
addresses: CWE-601

Security awareness includes verifying URLs and avoiding untrusted redirects that lead to malicious sites.

SI-10 Information Input Validation
addresses: CWE-601

Validates redirect targets and URLs to ensure they conform to allowed destinations.

References