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Fencer Intel
critical 9.1

CVE-2026-4599 json

jsrsasign: Incomplete Comparison Allows DSA Private Key Recovery via Biased Nonce Generation

published 7mo ago modified last mo. also GHSA-5jx8-q4cp-rhh6 , EUVD-2026-14373

cvss
9.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 42%
public exploits
0
none known

Summary

Versions of the package jsrsasign from 7.0.0 and before 11.1.1 are vulnerable to Incomplete Comparison with Missing Factors via the getRandomBigIntegerZeroToMax and getRandomBigIntegerMinToMax functions in src/crypto-1.1.js; an attacker can recover the private key by exploiting the incorrect compareTo checks that accept out-of-range candidates and thus bias DSA nonces during signature generation.

Patch / fix

  • npm jsrsasign 11.1.1
  • n/a jsrsasign 11.1.1
  • Red Hat Migration Toolkit for Virtualization 2.1 1779139872
  • Red Hat Migration Toolkit for Virtualization 2.9 1778927462
  • Red Hat Red Hat Quay 3.10 1775169155
  • Red Hat Red Hat Quay 3.12 1775253092
  • Red Hat Red Hat Quay 3.15 1775169219
  • Red Hat Red Hat Quay 3.16 1779204086
  • Red Hat Red Hat Quay 3.9 1775169218

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-4599 updated cvss 9.1

jsrsasign: jsrsasign: Private key recovery via incomplete comparison checks biasing DSA nonces

  • Red Hat Migration Toolkit for Virtualization mtv-candidate/mtv-console-plugin-rhel9
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Migration Toolkit for Virtualization 2.9 migration-toolkit-virtualization 1778927462
    fixed: vendor fix RHSA-2026:19410
  • Red Hat Migration Toolkit for Virtualization 2.10 migration-toolkit-virtualization 1779139872
    fixed: vendor fix RHSA-2026:19409
  • Red Hat Quay 3.9 quay 1775169218
    fixed: vendor fix RHSA-2026:6926
  • Red Hat Quay 3.10 quay 1775169155
    fixed: vendor fix RHSA-2026:6912
  • Red Hat Quay 3.12 quay 1775253092
    fixed: vendor fix RHSA-2026:6720
  • Red Hat Quay 3.15 quay 1775169219
    fixed: vendor fix RHSA-2026:6568
  • Red Hat Quay 3.16 quay 1779204086
    fixed: vendor fix RHSA-2026:19375
show 1 more
  • Red Hat Migration Toolkit for Virtualization 2.9 migration-toolkit-virtualization 1779084876, migration-toolkit-virtualization 1779085127, migration-toolkit-virtualization 1779085283, migration-toolkit-virtualization 1779085438, migration-toolkit-virtualization 1779085916, migration-toolkit-virtualization 1779085935, +5 more Red Hat Migration Toolkit for Virtualization 2.10 migration-toolkit-virtualization 1779138168, migration-toolkit-virtualization 1779138199, migration-toolkit-virtualization 1779138211, migration-toolkit-virtualization 1779138271, migration-toolkit-virtualization 1779138320, migration-toolkit-virtualization 1779138332, +7 more Red Hat Quay 3.9 quay 1774885670, quay 1774885680, quay 1774885682, quay 1774885717, quay 1774885725, quay 1774886457, +3 more Red Hat Quay 3.10 quay 1774885559, quay 1774885579, quay 1774885592, quay 1774885636, quay 1774885638, quay 1774886143, +1 more Red Hat Quay 3.12 quay 1774885546, quay 1774885564, quay 1774885572, quay 1774885604, quay 1774885641, quay 1774886107, +3 more Red Hat Quay 3.15 quay 1774979159, quay 1774979227, quay 1774980222, quay 1774980224, quay 1774984603, quay 1775183105, +3 more
    +1 more products
    Red Hat Quay 3.16 quay 1778704509, quay 1778704515, quay 1778704550, quay 1778704556, quay 1778705015, quay 1778705065, +3 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
7mo ago

Exploit prediction

0.50% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • gist.github.com https://gist.github.com/Kr0emer/081681818b51605c91945126d74b4f20 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 9.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CISA ADP 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CNA 4.0 9.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/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
GitHub 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
npm jsrsasign
>=7.0.0, <11.1.1
11.1.1

Affected products

  • n/a jsrsasign
  • n/a org.webjars.npm:jsrsasign
  • Red Hat Migration Toolkit for Virtualization 2.1
  • Red Hat Migration Toolkit for Virtualization 2.9
  • Red Hat Red Hat Quay 3.10
  • Red Hat Red Hat Quay 3.12
  • Red Hat Red Hat Quay 3.15
  • Red Hat Red Hat Quay 3.16
  • Red Hat Red Hat Quay 3.9

Classification

Weakness
  • CWE-1023 Incomplete Comparison with Missing Factors
  • CWE-338 Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.