CVE-2026-4603

MEDIUMNVD 5.35.9▲
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.9 under NVD CVSS v3. EPSS exploit probability: 0.0%, top 98% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
5.3
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.3Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Versions of the package jsrsasign before 11.1.1 are vulnerable to Division by zero due to the RSASetPublic/KEYUTIL parsing path in ext/rsa.js and the BigInteger.modPowInt reduction logic in ext/jsbn.js. An attacker can force RSA public-key operations (e.g., verify and encryption) to collapse to deterministic zero outputs and hide “invalid key” errors by supplying a JWK whose modulus decodes to zero.

CVSS v3
5.3
EG Score
5.9(medium)
EPSS
1.0%
KEV
Not listed

Published

March 23, 2026

Last Modified

June 22, 2026

Advisory Details (4)

Auto-updated Jun 22, 2026
⚠️ Active exploitation confirmed. Patch available. Sources: github_commit, github_pr.
generic🔴 Active Exploitation

Division by zero in jsrsasign | CVE-2026-4603 | Snyk

https://security.snyk.io/vuln/SNYK-JS-JSRSASIGN-15371176
github_pr Patch Available

fix(rsa): reject zero-modulus JWK keys and throw on BigInteger divide-by-zero

Patch available: kjur/jsrsasign 11.1.2 (PR #649 merged 2026-02-20)

https://github.com/kjur/jsrsasign/pull/649
github_commit Patch Available

commit dc41d49fac42 (kjur/jsrsasign)

Patch available: kjur/jsrsasign 11.1.2 (contains commit dc41d49fac42)

https://github.com/kjur/jsrsasign/commit/dc41d49fac4297e7a737a3ef8ebd0aa9c49ef93f
generic

zero-modulus.md · GitHub

https://gist.github.com/Kr0emer/5366b7364c4fbf7e754bc377f321e9f3

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFixed inDependents
jsrsasign—11.1.1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 4× in last 7d / 32× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-09 19:10 UTCEPSS rescore
  2. 2026-07-08 15:16 UTCEPSS rescore
  3. 2026-07-07 13:46 UTCEPSS rescore
  4. 2026-07-06 02:23 UTCEPSS rescore
  5. 2026-07-05 02:30 UTCEPSS rescore
  6. 2026-07-04 06:31 UTCEPSS rescore
  7. 2026-07-01 15:07 UTCEPSS rescore
  8. 2026-06-30 23:22 UTCEPSS rescore
  9. 2026-06-29 14:06 UTCEPSS rescore
  10. 2026-06-29 14:06 UTCEPSS rescore
  11. 2026-06-29 05:32 UTCOSV refresh
  12. 2026-06-28 14:07 UTCEPSS rescore
  13. 2026-06-28 04:56 UTCEPSS rescore
  14. 2026-06-28 04:56 UTCEPSS rescore
  15. 2026-06-27 03:08 UTCEPSS rescore
  16. 2026-06-25 13:49 UTCEPSS rescore
  17. 2026-06-24 14:05 UTCEPSS rescore
  18. 2026-06-23 21:33 UTCEPSS rescore
  19. 2026-06-23 21:33 UTCEPSS rescore
  20. 2026-06-22 03:40 UTCNVD updateCVSS v3 → 5.3 · CVSS v4 → 2
  21. 2026-06-21 01:59 UTCEPSS rescore
  22. 2026-06-21 01:59 UTCEPSS rescore
  23. 2026-06-18 17:52 UTCEPSS rescore
  24. 2026-06-18 17:52 UTCEPSS rescore
  25. 2026-06-17 17:53 UTCEPSS rescore
Show 48 more
  1. 2026-06-16 17:53 UTCEPSS rescore
  2. 2026-06-15 17:49 UTCEPSS rescore
  3. 2026-06-15 17:49 UTCEPSS rescore
  4. 2026-06-14 23:18 UTCEPSS rescore
  5. 2026-06-13 23:00 UTCEPSS rescore
  6. 2026-06-12 23:12 UTCEPSS rescore
  7. 2026-06-12 23:12 UTCEPSS rescore
  8. 2026-06-11 23:36 UTCEG score recompute
  9. 2026-06-11 14:00 UTCEPSS rescore
  10. 2026-06-10 22:19 UTCEPSS rescore
  11. 2026-06-10 15:11 UTCEG score recompute
  12. 2026-06-10 13:22 UTCEPSS rescore
  13. 2026-06-09 16:09 UTCEG score recompute
  14. 2026-06-08 14:47 UTCEG score recompute
  15. 2026-06-08 14:17 UTCEPSS rescore
  16. 2026-06-08 14:17 UTCEPSS rescore
  17. 2026-06-07 15:25 UTCEPSS rescore
  18. 2026-06-07 15:25 UTCEPSS rescore
  19. 2026-06-07 13:35 UTCEG score recompute
  20. 2026-06-06 13:47 UTCEPSS rescore
  21. 2026-06-06 13:47 UTCEPSS rescore
  22. 2026-06-05 22:47 UTCEPSS rescore
  23. 2026-06-05 06:10 UTCEPSS rescore
  24. 2026-06-05 06:10 UTCEPSS rescore
  25. 2026-06-04 13:12 UTCEPSS rescore
  26. 2026-06-04 13:12 UTCEPSS rescore
  27. 2026-06-02 20:13 UTCEPSS rescore
  28. 2026-06-01 13:52 UTCEPSS rescore
  29. 2026-06-01 13:52 UTCEPSS rescore
  30. 2026-06-01 07:43 UTCOSV refresh
  31. 2026-05-31 22:30 UTCEPSS rescore
  32. 2026-05-31 22:30 UTCEPSS rescore
  33. 2026-05-31 00:16 UTCEPSS rescore
  34. 2026-05-31 00:16 UTCEPSS rescore
  35. 2026-05-29 13:44 UTCEPSS rescore
  36. 2026-05-29 13:44 UTCEPSS rescore
  37. 2026-05-28 13:44 UTCEPSS rescore
  38. 2026-05-28 13:44 UTCEPSS rescore
  39. 2026-05-27 13:40 UTCEPSS rescore
  40. 2026-05-27 13:40 UTCEPSS rescore
  41. 2026-05-26 13:44 UTCEPSS rescore
  42. 2026-05-26 07:18 UTCEPSS rescore
  43. 2026-05-23 00:09 UTCEG score recompute
  44. 2026-05-21 22:43 UTCEPSS rescore
  45. 2026-05-20 22:38 UTCEPSS rescore
  46. 2026-05-20 20:39 UTCEG score recompute
  47. 2026-05-20 11:22 UTCEPSS rescore
  48. 2026-05-19 15:03 UTCOSV refresh

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-4603?
CVE-2026-4603 is a medium vulnerability published on March 23, 2026. Versions of the package jsrsasign before 11.1.1 are vulnerable to Division by zero due to the RSASetPublic/KEYUTIL parsing path in ext/rsa.js and the BigInteger.modPowInt reduction logic in ext/jsbn.js. An attacker can force RSA public-key operations (e.g., verify and encryption) to collapse to…
When was CVE-2026-4603 disclosed?
CVE-2026-4603 was first published in the National Vulnerability Database on March 23, 2026, with the most recent update on June 22, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-4603 actively exploited?
CVE-2026-4603 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-4603?
CVE-2026-4603 has a CVSS v3 base score of 5.3 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 5.9.
How do I remediate CVE-2026-4603?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-4603, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-4603

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