CVE-2026-4601
Kjur Jsrsasign ≤ 11.1.1
Raw vector
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:H/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XSummary
CVE-2026-4601 is a high-severity Missing Cryptographic Step (CWE-325) vulnerability in Kjur Jsrsasign. Its CVSS base score is 8.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Weaken Encryption (T1600); ranked at the 22th percentile by exploit likelihood (below the median); 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 SA-11 (Developer Testing and Evaluation) and SC-13 (Cryptographic Protection) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-4601 affects versions of the jsrsasign JavaScript package prior to 11.1.1, specifically in the KJUR.crypto.DSA.signWithMessageHash process within its DSA signing implementation. The vulnerability stems from a missing cryptographic step (CWE-325), where the library fails to retry signature generation upon producing an invalid signature. This allows an attacker to recover the private key by manipulating the process to force the r or s value in the signature to zero, enabling straightforward mathematical solving for the private key from the emitted invalid signature.
A remote attacker with no privileges or user interaction required can exploit this over the network, though it demands high attack complexity and results in a scope change. Successful exploitation grants high confidentiality and integrity impacts, primarily through private key recovery, which could compromise DSA-based signatures and enable forgery or decryption in affected applications relying on jsrsasign for cryptographic operations.
Advisories and patches, including the fix in jsrsasign commit 0710e392ec35de697ce11e4219c988ba2b5fe0eb and pull request 645, recommend updating to version 11.1.1 or later to address the issue by ensuring proper retry logic for invalid signatures. Snyk's vulnerability report (SNYK-JS-JSRSASIGN-15370941) details the flaw, while a GitHub Gist provides additional technical context on the exploit mechanics.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-14377
Vulnerability Data
Versions of the package jsrsasign before 11.1.1 are vulnerable to Missing Cryptographic Step via the KJUR.crypto.DSA.signWithMessageHash process in the DSA signing implementation. An attacker can recover the private key by forcing r or s to be zero, so the library…
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emits an invalid signature without retrying, and then solves for x from the resulting signature.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 14 hardening rules · 6 OS baselines
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Mitigating Controls (NIST 800-53 r5) AI
Requires selection and implementation of specific approved cryptographic algorithms and methods, reducing the chance that an incomplete algorithm is used.
Mandates developer testing and evaluation that can uncover missing cryptographic steps through functional and penetration testing.
Requires documented development standards and processes that include correct cryptographic algorithm implementation.
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.
Secure SDLC practices explicitly include correct cryptographic algorithm implementation and testing.
Proper encryption of data-at-rest requires all algorithm steps; omitting one directly weakens the control.
Proper encryption of data-in-transit requires all algorithm steps; omitting one directly weakens the control.
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.
Security testing can detect incomplete crypto implementations but does not itself enforce correct algorithm steps.
Mandates correct use of cryptographic controls, directly preventing omission of required algorithm steps.
Secure SDLC processes reduce the likelihood of missing crypto steps but do not guarantee algorithm completeness.
Requires secure coding practices that would catch missing cryptographic steps during development.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).
Oracle Linux 8 (2 rules)
- V-248524 OL 8 must implement NIST FIPS-validated cryptography for the following: To provision digital signatures, to generate cryptographic hashes, and to protect data requiring data-at-rest protections in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-325
- V-248535 The OL 8 shadow password suite must be configured to use a sufficient number of hashing rounds. prevents CWE-325
Oracle Linux 9 (1 rule)
- V-271454 OL 9 must enable FIPS mode. prevents CWE-325
RHEL 7 (1 rule)
- V-204497 The Red Hat Enterprise Linux operating system must implement NIST FIPS-validated cryptography for the following: to provision digital signatures, to generate cryptographic hashes, and to protect data requiring data-at-rest protections in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-325
RHEL 8 (1 rule)
- V-230223 RHEL 8 must implement NIST FIPS-validated cryptography for the following: To provision digital signatures, to generate cryptographic hashes, and to protect data requiring data-at-rest protections in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-325
Ubuntu 22.04 (1 rule)
- V-260650 Ubuntu 22.04 LTS must implement NIST FIPS-validated cryptography to protect classified information and for the following: To provision digital signatures, to generate cryptographic hashes, and to protect unclassified information requiring confidentiality and cryptographic protection in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-325
Ubuntu 24.04 (1 rule)
- V-270744 Ubuntu 24.04 LTS must implement NIST FIPS-validated cryptography to protect classified information and for the following: To provision digital signatures, to generate cryptographic hashes, and to protect unclassified information requiring confidentiality and cryptographic protection in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-325