CVE-2026-4602Public exploitNetwork attack vector

Signature verification bypass via negative exponent mishandling

Published Mar 23, 2026 · Updated Mar 23, 2026

Incorrect numeric conversion in jsrsasign before 11.1.1 allows remote attackers to interrupt signature verification via a negative exponent. BigInteger.modPow in ext/jsbn2.js treats a negative exponent as having a nonpositive bit length and returns 1 instead of computing the modular inverse. The affected API must process an attacker-controlled exponent in a network-facing consumer; the invalid arithmetic breaks verification without exposing keys or data.

CVSS severity7.5
High
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect numeric conversion in jsrsasign before 11.1.1 allows remote attackers to interrupt signature verification via a negative exponent. BigInteger.modPow in ext/jsbn2.js treats a negative exponent as having a nonpositive bit length and returns 1 instead of computing the modular inverse. The affected API must process an attacker-controlled exponent in a network-facing consumer; the invalid arithmetic breaks verification without exposing keys or data.

The record

CVE
CVE-2026-4602
Published
Mar 23, 2026
Updated
Mar 23, 2026
Vendor
jsrsasign project
Product
jsrsasign
Classifications
CWE-681, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 23, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <11.1.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

jsrsasign project · jsrsasignversion=0 <11.1.1

Published CVSS scores

7.5SnykCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.7SnykCVSS: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
7.5Red Hat Security ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-681Incorrect Conversion between Numeric Types
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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