jsrsasign: Improper Verification of Cryptographic Signature
CVE-2026-4600 is a critical-severity improper verification of cryptographic signature vulnerability in jsrsasign, with a CVSS 3.1 base score of 9.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 11.1.1 as the first without the flaw, so updating jsrsasign to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.36% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update jsrsasign to 11.1.1 or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Jsrsasign | jsrsasign | before 11.1.1 | 11.1.1 |
| Org.webjars.npm:jsrsasign | org.webjars.npm:jsrsasign | all versions | Not stated |
| Red Hat | Migration Toolkit for Virtualization 2.1 | Not specified in the record | Not stated |
| Red Hat | Migration Toolkit for Virtualization 2.9 | Not specified in the record | Not stated |
| Red Hat | Red Hat Quay 3.10 | Not specified in the record | Not stated |
| Red Hat | Red Hat Quay 3.12 | Not specified in the record | Not stated |
| Red Hat | Red Hat Quay 3.15 | Not specified in the record | Not stated |
| Red Hat | Red Hat Quay 3.16 | Not specified in the record | Not stated |
| Red Hat | Red Hat Quay 3.9 | Not specified in the record | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.1 | High | CNA (snyk.io) |
| CVSS 3.1 | 7.4 | High | CNA (snyk.io) |
| CVSS 3.1 | 9.1 | Critical | NVD |
| CVSS 3.1 | 8.2 | High | CNA |
Official description
Versions of the package jsrsasign before 11.1.1 are vulnerable to Improper Verification of Cryptographic Signature via the DSA domain-parameter validation in KJUR.crypto.DSA.setPublic (and the related DSA/X509 verification flow in src/dsa-2.0.js). An attacker can forge DSA signatures or X.509 certificates that X509.verifySignature() accepts by supplying malicious domain parameters such as g=1, y=1, and a fixed r=1, which make the verification equation true for any hash.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Verification of Cryptographic Signature
The product does not verify, or incorrectly verifies, the cryptographic signature for data.
More Improper Verification of Cryptographic Signature vulnerabilities (CWE-347)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- gist.github.com/Kr0emer/bf15ddc097176e951659a24a8e9002a7Exploit, Mitigation, Third Party Advisory
- github.com/kjur/jsrsasign/commit/37b4c06b145c7bfd6bc2a6df5d0a12c56b15ef60
- github.com/kjur/jsrsasign/pull/646Issue Tracking
Third-party and government advisories
- security.snyk.io/vuln/SNYK-JS-JSRSASIGN-15370940Third Party Advisory
Other references
- security.snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-15812268
- access.redhat.com/errata/RHSA-2026:19375
- access.redhat.com/errata/RHSA-2026:19409
- access.redhat.com/errata/RHSA-2026:19410
- access.redhat.com/errata/RHSA-2026:6568
- access.redhat.com/errata/RHSA-2026:6720
- access.redhat.com/errata/RHSA-2026:6912
- access.redhat.com/errata/RHSA-2026:6926
- access.redhat.com/security/cve/CVE-2026-4600
- bugzilla.redhat.com/show_bug.cgi?id=2450208
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4600.json
Other vulnerabilities in jsrsasign
- 7.5 High severity
- 9.1 Critical severity
- 9.1 Critical severity
- 7.5 High severity
- 9.8 Critical severity
Recent Improper Verification of Cryptographic Signature vulnerabilities
- 9.0 Critical severity
- 7.5 High severity
- 9.1 Critical severity
- 8.8 High severity
- 7.5 High severity
- 9.8 Critical severity
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