CVE-2026-58063: Bouncycastle · In Bouncy Castle for Java before 1.85, BCFKS keystore load honours unbounded KDF cost from untrusted file
Affects bouncycastleSource GCVE Database
Not known to be exploited · CVSS 5.3 Medium : upgrade to 1.85 when convenient.
Data as of 1 Nov 2026, 22:58 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 36% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.85
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/U:AmberExploitation evidence
Disclosed: evidence found.
CVE published 3 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 1 Nov 2026.
What to do
Upgrade org.bouncycastle/bcprov-jdk15on to 1.85.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu Pro 16.04 LTSbouncycastlepkg:deb/ubuntu/bouncycastle?arch=source&distro=esm-apps/xenialOther threats | Affected
| Fixed in– |
Ubuntu Pro 18.04 LTSbouncycastlepkg:deb/ubuntu/bouncycastle?arch=source&distro=esm-apps/bionicOther threats | Affected
| Fixed in– |
Ubuntu Pro 20.04 LTSbouncycastlepkg:deb/ubuntu/bouncycastle?arch=source&distro=esm-apps/focalOther threats | Affected
| Fixed in– |
Ubuntu Pro 22.04 LTSbouncycastlepkg:deb/ubuntu/bouncycastle?arch=source&distro=esm-apps/jammyOther threats | Affected
| Fixed in– |
Ubuntu Pro 24.04 LTSbouncycastlepkg:deb/ubuntu/bouncycastle?arch=source&distro=esm-apps/nobleOther threats | Affected
| Fixed in– |
Ubuntu 26.10bouncycastlepkg:deb/ubuntu/bouncycastle?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
If you cannot patch yet, avoid loading untrusted BCFKS keystore files or implement resource usage limits around keystore loading operations to mitigate potential denial of service.
Description
Bouncy Castle for Java versions prior to 1.85 and certain LTS and FIPS versions improperly honor an unbounded key derivation function (KDF) cost parameter from untrusted BCFKS keystore files during load. This vulnerability could lead to resource exhaustion or denial of service due to excessive computational cost. The issue affects Bouncy Castle for Java, including LTS versions before 2.73.12 and FIPS versions before bc-fips 1.0.2.7 (1.0.X), 2.0.2 (2.0.X), and 2.1.3 (2.1.X). No known exploits are reported in the wild. The severity is assessed as medium based on available data.
References
- nvd.nist.gov/vuln/detail/CVE-2026-58063 (opens in a new tab)
- github.com/bcgit/bc-java/commit/81737a56ef4489da1f849cf549df95e338ea6b06 (opens in a new tab)
- github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9058063 (opens in a new tab)
- github.com/bcgit/bc-java/wiki/CVE-2026-58063 (opens in a new tab)
- ubuntu.com/security/CVE-2026-58063 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-58063 (opens in a new tab)