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Public proof of conceptFix available

CVE-2026-4598

A public proof of concept exists; no exploitation attested.

  • Published2026-03-23
  • Fixed in11.1.1
  • WeaknessCWE-1287 · CWE-835

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Versions of the package jsrsasign before 11.1.1 are vulnerable to Infinite loop via the bnModInverse function in ext/jsbn2.js when the BigInteger.modInverse implementation receives zero or negative inputs, allowing an attacker to hang the process permanently by supplying such crafted values (e.g., modInverse(0, m) or modInverse(-1, m)).

Timeline

dates in UTC
  1. 2026-03-2306:16CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-4598?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-4598?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV
Kjur jsrsasign
BranchAffectedFixed in
11.1< 11.1.111.1.1

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • RHSA-2026:23361 Red Hat Product Security3 products fixed

    Red Hat Security Advisory: Red Hat Quay 3.9.22

  • RHSA-2026:22840 Red Hat Product Security3 products fixed

    Red Hat Security Advisory: Red Hat Quay 3.10.22

  • RHSA-2026:19375 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: Red Hat Quay 3.16.4

  • RHSA-2026:6720 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: Red Hat Quay 3.12.16

Full record on NVD

Fix

  1. Update Kjur jsrsasign to 11.1.1
  2. Vendor fix Red Hat Product Security RHSA-2026:23361 · 3 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
  3. Workaround from the vendor Red Hat Product Security RHSA-2026:23361 · 22 productsMitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • NVDCVE recordread 2026-10-23
  • CISA-ADPSSVC decisionpoc2026-03-23
  • OpenCVESSVC decisionpoc—
  • CNACVSS 4.07.7read 2026-10-23
  • CNACVSS 3.17.5read 2026-10-23
  • CNAweakness (CWE)CWE-1287, CWE-835read 2026-10-23
  • FIRST EPSSEPSS score1.0 %2026-10-22
  • OSVaffected packages—

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 4.0 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/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:X
Published
2026-03-23
Last Modified
2026-09-10
NVD status
Modified

Frequently asked questions

What is CVE-2026-4598?

Versions of the package jsrsasign before 11.1.1 are vulnerable to Infinite loop via the bnModInverse function in ext/jsbn2.js when the BigInteger.modInverse implementation receives zero or negative inputs, allowing an attacker to hang the process permanently by supplying such crafted values (e.g., modInverse(0, m) or modInverse(-1, m)).

Is CVE-2026-4598 actively exploited?

A proof-of-concept exploit exists for CVE-2026-4598, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2026-4598?

CVE-2026-4598 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Running jsrsasign? Hear about its next vulnerability

Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

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