BC-JAVA: Covert Timing Channel
CVE-2026-5598 is a high-severity covert timing channel vulnerability in BC-JAVA from Legion of the Bouncy Castle, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 1.80.2, 1.81.1, 1.84 as the first without the flaw, so updating BC-JAVA to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.17% chance of exploitation within 30 days, higher than 68% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update BC-JAVA to 1.80.2 or 1.81.1 or 1.84, whichever matches your release line, or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from the organisation that assigned the CVE; 7 further products are omitted here. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.9 | High | CNA |
| CVSS 3.1 | 7.5 | High | CNA |
Official description
Covert timing channel vulnerability in Legion of the Bouncy Castle Inc. BC-JAVA core on all (core modules). This vulnerability is associated with program files FrodoEngine.Java. This issue affects BC-JAVA: from 1.71 before 1.80.2, from 1.81 before 1.81.1, from 1.82 before 1.84.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Covert Timing Channel
Covert timing channels convey information by modulating some aspect of system behavior over time, so that the program receiving the information can observe system behavior and infer protected information.
How developers prevent this class of flaw
- Whenever possible, specify implementation strategies that do not introduce time variances in operations.
- Often one can artificially manipulate the time which operations take or -- when operations occur -- can remove information from the attacker.
- It is reasonable to add artificial or random delays so that the amount of CPU time consumed is independent of the action being taken by the application.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
- github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%905598
- access.redhat.com/errata/RHSA-2026:12267
- access.redhat.com/errata/RHSA-2026:12269
- access.redhat.com/errata/RHSA-2026:18054
- access.redhat.com/errata/RHSA-2026:18055
- access.redhat.com/errata/RHSA-2026:18059
- access.redhat.com/errata/RHSA-2026:53644
- access.redhat.com/errata/RHSA-2026:53645
- access.redhat.com/errata/RHSA-2026:53646
- access.redhat.com/security/cve/CVE-2026-5598
- bugzilla.redhat.com/show_bug.cgi?id=2458635
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-5598.json
Other vulnerabilities in BC-JAVA
- 8.2 High severity
- 7.1 High severity
- 8.7 High severity
- 8.7 High severity
- 8.7 High severity
- 8.2 High severity
Recent Covert Timing Channel vulnerabilities
- 7.5 High severity
- 7.4 High severity
- 7.4 High severity
- 7.5 High severity
- 7.5 High severity
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