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TI-2026-42535 Aliases CVE-2026-59640GHSA-w983-hf44-gcww

OpenPGP CFB quick-check oracle active on symmetric/session-key paths

Priority MEDIUM 44CWE-203Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Information disclosure
Confidentiality · integrity · availability
High · None · None
Fix status
Partial Red Hat: 2 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-203.

Summary

In Bouncy Castle for Java before 1.85, OpenPGP CFB quick-check oracle active on symmetric/session-key paths. This issue also affects Bouncy Castle for Java LTS before 2.73.12, and Bouncy Castle for Java FIPS (BC-FJA) before bcpg-fips 1.0.13 (1.0.X series), 2.0.13 (2.0.X series) and 2.1.13 (2.1.X series).

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00347 28th percentileScored 2026-11-07
Fix Partial BC-JAVA (Legion of the Bouncy Castle Inc.): 1.85BC-LTS-JAVA (Legion of the Bouncy Castle Inc.): 2.73.12+1 more productRed Hat: 2 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Legion of the Bouncy Castle Inc.BC-JAVAbefore 1.851.85Patch availableCNA
Legion of the Bouncy Castle Inc.BC-LTS-JAVA2.73.0 to before 2.73.122.73.12Patch availableCNA
Legion of the Bouncy Castle Inc.BC-FJA1.0.0 to before 1.0.13; 2.0.0 to before 2.0.13; 2.1.0 to before 2.1.131.0.13, 2.0.13, 2.1.13Patch availableCNA

CPE configurations NVD · 3

CPEVersionsRoleVendor
cpe:2.3:a:bouncycastle:bc-java:*:*:*:*:*:*:*:*before 1.85VulnerableLegion of the Bouncy Castle Inc.
cpe:2.3:a:bouncycastle:bcpg-fips:*:*:*:*:*:*:*:*before 1.0.13; 2.0.8 to before 2.0.13; 2.1.10 to before 2.1.13VulnerableLegion of the Bouncy Castle Inc.
cpe:2.3:a:bouncycastle:bouncy_castle_for_java_lts:*:*:*:*:*:*:*:*up to 2.73.11VulnerableLegion of the Bouncy Castle Inc.

Remediation

  • Fix · CNA BC-JAVA (Legion of the Bouncy Castle Inc.) Fixed in 1.85
  • Fix · CNA BC-LTS-JAVA (Legion of the Bouncy Castle Inc.) Fixed in 2.73.12
  • Fix · CNA BC-FJA (Legion of the Bouncy Castle Inc.) Fixed in 1.0.13, 2.0.13, 2.1.13

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    Legion of the Bouncy Castle BC-JAVA 1.85

    32 records Highest priority Priority MEDIUM 23 MEDIUM, 9 LOW

    Other records, highest priority first

    • TI-2026-42545 MTI/A0 DH agreement exponentiates unvalidated peer valuePriority MEDIUM 48
    • TI-2026-42533 JSSE hostname verifier CN-fallback enabled by default despite documented opt-inPriority MEDIUM 48
    • TI-2026-41816 Stapled OCSP response accepted without binding to the checked certificatePriority MEDIUM 48
    Show all 32 records →
  • Release ·

    Legion of the Bouncy Castle BC-LTS-JAVA 2.73.12

    28 records Highest priority Priority MEDIUM 20 MEDIUM, 8 LOW

    Other records, highest priority first

    • TI-2026-42545 MTI/A0 DH agreement exponentiates unvalidated peer valuePriority MEDIUM 48
    • TI-2026-42533 JSSE hostname verifier CN-fallback enabled by default despite documented opt-inPriority MEDIUM 48
    • TI-2026-41816 Stapled OCSP response accepted without binding to the checked certificatePriority MEDIUM 48
    Show all 28 records →
Show 1 more group
  • Release ·

    Legion of the Bouncy Castle BC-FJA 1.0.13, 2.0.13, 2.1.13

    4 records Highest priority Priority MEDIUM 3 MEDIUM, 1 LOW

    Other records, highest priority first

    • TI-2026-42544 OpenPGP user-attribute subpacket length bounded only by JVM max memoryPriority MEDIUM 44
    • TI-2026-10955 OpenPGP AEAD decryption skips final tag on chunk-aligned dataPriority MEDIUM 43
    • TI-2026-42543 OpenPGP Argon2 S2K honours attacker-chosen memory and passesPriority LOW 31
    Show all 4 records →

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat JBoss Enterprise Application Platform 7AffectedNo fix planned: Will not fix
Red Hat Single Sign-On 7AffectedNo fix planned: Will not fix

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-59640
  2. 2026-10-03 Alias added: GHSA-w983-hf44-gcww
  3. 2026-10-16 Affected versions changed · Red Hat

References

Patch 1

Advisory 1

  • TI-2018-15967 Legion of the Bouncy Castle Legion of the Bouncy Castle Java Cryptography APIs 1.58 up to… CVSS 3.1CRITICAL 9.8
  • TI-2017-09736 BouncyCastle JCE TLS Bleichenbacher/ROBOT CVSS 3.0HIGH 7.5
  • TI-2026-42545 MTI/A0 DH agreement exponentiates unvalidated peer value CVSS 4.0CRITICAL 9.3
  • TI-2026-42533 JSSE hostname verifier CN-fallback enabled by default despite documented opt-in CVSS 4.0CRITICAL 9.3
  • TI-2026-41816 Stapled OCSP response accepted without binding to the checked certificate CVSS 4.0CRITICAL 9.3
  • TI-2026-07701 Name Constraints bypass via trailing dot in rfc822Name and URI CVSS 4.0CRITICAL 9.3
See all 52 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences