Security Resilience

CVE-2024-21484

Kjur Jsrsasign ≤ 11.0.0

Public PoC
Published
22 January 2024
Modified
22 June 2026
Patch / advisory
View advisory
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:L
EPSS Score 0.0096 61th percentile
Risk Priority 56 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2024-21484 is a high-severity Observable Discrepancy (CWE-203) vulnerability in Kjur Jsrsasign. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Steganography (T1001.002); ranked in the top 39% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to IA-6 (Authentication Feedback) and SI-11 (Error Handling) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

Versions of the package jsrsasign before 11.0.0 are vulnerable to Observable Discrepancy via the RSA PKCS1.5 or RSAOAEP decryption process. An attacker can decrypt ciphertexts by exploiting the Marvin security flaw. Exploiting this vulnerability requires the attacker to have access…

more

to a large number of ciphertexts encrypted with the same key. Workaround The vulnerability can be mitigated by finding and replacing RSA and RSAOAEP decryption with another crypto library.

CWE(s)
CWE-203

Related Threats

MITRE ATT&CK Enterprise Techniques

T1001.002 Steganography Command And Control
Adversaries may use steganographic techniques to hide command and control traffic to make detection efforts more difficult.
attack.mitre.org →
T1003.003 NTDS Credential Access
Adversaries may attempt to access or create a copy of the Active Directory domain database in order to steal credential information, as well as obtain other information about domain members such as devices, users, and access rights.
attack.mitre.org →
T1003.004 LSA Secrets Credential Access
Adversaries with SYSTEM access to a host may attempt to access Local Security Authority (LSA) secrets, which can contain a variety of different credential materials, such as credentials for service accounts.
attack.mitre.org →
T1011 Exfiltration Over Other Network Medium Exfiltration
Adversaries may attempt to exfiltrate data over a different network medium than the command and control channel.
attack.mitre.org →
T1011.001 Exfiltration Over Bluetooth Exfiltration
Adversaries may attempt to exfiltrate data over Bluetooth rather than the command and control channel.
attack.mitre.org →
T1012 Query Registry Discovery
Adversaries may interact with the Windows Registry to gather information about the system, configuration, and installed software.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-4598Same product: Kjur Jsrsasign
CVE-2026-4599Same product: Kjur Jsrsasign
CVE-2026-4602Same product: Kjur Jsrsasign
CVE-2026-4601Same product: Kjur Jsrsasign
CVE-2026-4600Same product: Kjur Jsrsasign
CVE-2023-39522Shared CWE-203
CVE-2023-5388Shared CWE-203
CVE-2023-50979Shared CWE-203
CVE-2025-36225Shared CWE-203
CVE-2023-28015Shared CWE-203

Affected Assets

kjur
jsrsasign
≤ 11.0.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 1 hardening rule · 1 OS baseline
Validate
Prove the fix (OWASP ASVS)

—

Mitigating Controls (NIST 800-53 r5) AI

IA-6 Authentication Feedback good match

Obscures authentication feedback so that success/failure differences are not observable to attackers.

SI-11 Error Handling good match

Requires error messages to avoid revealing exploitable details, directly stopping observable response discrepancies.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 partial match
blocks

Secure SDLC practices directly prevent observable response discrepancies via consistent error handling and timing.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.5.14 Information transfer partial match
removes
A.5.15 Access control partial match
removes
A.5.16 Identity management partial match
removes
A.5.17 Authentication information partial match
removes
A.5.18 Access rights partial match
removes
A.6.8 Information security event reporting partial match
removes

References