Cyber Resilience

CVE-2021-24020

High

Published: 09 July 2021

Published
09 July 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0017 38.1th percentile
Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-24020 is a high-severity Improper Verification of Cryptographic Signature (CWE-347) vulnerability in Fortinet Fortimail. Its CVSS base score is 7.5 (High).

Operationally, ranked at the 38.1th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

A missing cryptographic step in the implementation of the hash digest algorithm in FortiMail 6.4.0 through 6.4.4, and 6.2.0 through 6.2.7 may allow an unauthenticated attacker to tamper with signed URLs by appending further data which allows bypass of signature…

more

verification.

CWE(s)

Related Threats

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

Affected Assets

fortinet
fortimail
6.2.0 — 6.2.7 · 6.4.0 — 6.4.5

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.

addresses: CWE-347

Requires verification of digital signatures using organization-approved certificates before installation, directly preventing improper verification of cryptographic signatures.

addresses: CWE-347

Component authenticity commonly depends on cryptographic signatures; the control enforces proper verification of those signatures.

addresses: CWE-347

PKI certificates under an approved policy require cryptographic signature verification on issuance and validation.

addresses: CWE-347

Requires cryptographic signatures on authoritative data and support for verifying the chain of trust.

addresses: CWE-347

Mandates verification of cryptographic signatures (e.g., DNSSEC RRSIG) on resolution responses, addressing missing or bypassed signature checks.

addresses: CWE-347

Integrity tools commonly rely on cryptographic signatures whose improper validation this weakness covers.

addresses: CWE-347

Authenticity validation commonly relies on cryptographic signature or certificate checks that this control enforces.

References