MEDIUM
CVE-2026-4603
CWE-369Published: March 23, 2026· Updated: Mar 23, 2026
5.3
CVSS v3.1
EPSS:0.01%probability of exploitation in 30 daysPercentile:0.8th
Official Description
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.
Technical Analysis
CVE-2026-4603 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CVSS v3.1 Vector Breakdown
Exploitability
Attack VectorLocal
Attack ComplexityLow
Privileges Req.Low
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityLow
IntegrityLow
AvailabilityLow
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
Affected Vendors & Products
jsrsasign_project1 product
jsrsasign
Source: NVD CPE · 1 total CPE entries
Exploit & PoC Resources
NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
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Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
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Official Patches & Advisories
All References (4)
→
https://gist.github.com/Kr0emer/5366b7364c4fbf7e754bc377f321e9f3Exploit · Mitigation · Third Party Advisory
→
https://github.com/kjur/jsrsasign/pull/649Issue Tracking
→
https://security.snyk.io/vuln/SNYK-JS-JSRSASIGN-15371176Third Party Advisory
Quick Facts
CVE IDCVE-2026-4603
CVSS Score5.3 / 10
SeverityMEDIUM
WeaknessCWE-369
CISA KEVNo
EPSS (30d)0.01%
Affected1 vendor
PublishedMar 23, 2026
Related CVEs (CWE-369)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-4603 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.