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CVE Record

CVE-2026-4602: Versions of the package jsrsasign before 11.1.1 are vulnerable to Incorrect Conversion between Numeric Type...

Versions of the package jsrsasign before 11.1.1 are vulnerable to Incorrect Conversion between Numeric Types due to handling negative exponents in ext/jsbn2.js. An attacker can force the computation of incorrect modular inverses and break signature verification by calling modPow with a negative exponent.

HighCVSS 8.7Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2026-4602 affects jsrsasign versions before 11.1.1. A math-conversion flaw can make cryptographic calculations return wrong results, potentially undermining signature verification. Treat this as high priority where jsrsasign protects authentication, tokens, documents, or signed data.

Executive priority

Prioritize remediation this cycle for systems relying on jsrsasign for trust decisions. The flaw targets cryptographic verification, has public proof-of-concept signals, and affects a common JavaScript package, but current sources do not prove active exploitation.

Technical view

The issue is CWE-681 in ext/jsbn2.js: handling of negative exponents in modPow can force incorrect modular inverse computation. Sources describe impact as breaking signature verification. The CVSS 4.0 score is 8.7 high, with network, unauthenticated, low-complexity attack characteristics and proof-of-concept maturity indicated.

Likely exposure

Exposure is most likely in applications or bundled products using jsrsasign before 11.1.1, including org.webjars.npm:jsrsasign. Risk is highest where untrusted data reaches jsrsasign cryptographic verification paths.

Exploitation context

The bundle does not show CISA KEV listing or active exploitation. It does include a public gist reference and CVSS exploit maturity marked proof-of-concept, so defenders should assume public technical detail exists without treating this as known in-the-wild exploitation.

Researcher notes

Key research focus is reachability: identify whether vulnerable modPow behavior is reachable through signature verification in the application’s use of jsrsasign. Avoid assuming every install is exploitable, but treat exposed verification workflows as higher risk.

Mitigation direction

  • Upgrade jsrsasign to 11.1.1 or later where the package is directly used.
  • Update org.webjars.npm:jsrsasign dependencies to a non-vulnerable release when available.
  • Apply relevant Red Hat RHSA updates for affected Red Hat-maintained packages.
  • Check vendor guidance for products that bundle jsrsasign indirectly.
  • Prioritize systems where jsrsasign validates authentication tokens or signed business data.

Validation and detection

  • Inventory npm, lockfile, Maven, and WebJars dependencies for jsrsasign versions before 11.1.1.
  • Confirm dependency scanners no longer report SNYK-JS-JSRSASIGN-15371175 or SNYK-JAVA-ORGWEBJARSNPM-15812274.
  • Review whether untrusted inputs can reach jsrsasign signature verification or modPow-related code paths.
  • Verify deployed artifacts contain the upgraded dependency, not only source manifests.
  • Track Red Hat errata status for any downstream packages in use.
Prepared
Confidence
high
Sources
12

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-681: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2026-4602 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
8.7 (4.0)
Known Exploited
No
Published

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

3CVSS vectors
5Timeline events
2ADP providers
16Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: pocAutomatable: yesTechnical Impact: partial

CVSS vector scores

3 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
8.7CVSS 4.0HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P——snyk
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P3.93.6snyk
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N3.93.6redhat-SADP

Vulnerability scoring details

Base CVSS 4.0 score

8.7High
CVSS 4.0 vector shape for CVE-2026-4602Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Attack Requirements
NonePresent
Privileges Required
NoneLowHigh
User Interaction
NonePassiveActive
VS Confidentiality
HighLowNone
VS Integrity
HighLowNone
VS Availability
HighLowNone
SS Confidentiality
HighLowNone
SS Integrity
HighLowNone
SS Availability
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPjsrsasign: jsrsasign: Signature verification bypass via negative exponent handling
other:Red Hat severity ratingcvssV3_1
  • 2026-03-23T06:01:28.729Z: Reported to Red Hat.
  • 2026-03-23T05:00:10.567Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/ajsrsasign0Listed
n/aorg.webjars.npm:jsrsasign0Listed
Weakness

CWE details

CWE-681

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-681 · source CWE mapping

Incorrect Conversion between Numeric Types

Incorrect Conversion between Numeric Types represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs