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VulnerabilityPublished Updated

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

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Authoritative record:CVE-2026-58063· Medium 5.3

Not known to be exploited · CVSS 5.3 Medium : upgrade to 1.85 when convenient.

Data as of 1 Nov 2026, 22:58 UTC

CVSS 4.0 base score
5.3Medium
How severe the flaw is on the 0–10 CVSS scale.
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:Amber

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 3 Aug 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
Ubuntu Pro 16.04 LTSbouncycastlepkg:deb/ubuntu/bouncycastle?arch=source&distro=esm-apps/xenialOther threatsAffected
  • =1.49+dfsg-3ubuntu1
  • =1.51-4ubuntu1
  • =1.51-4ubuntu1+esm1
Fixed in–
Ubuntu Pro 18.04 LTSbouncycastlepkg:deb/ubuntu/bouncycastle?arch=source&distro=esm-apps/bionicOther threatsAffected
  • 1.57-1 – 1.59-1ubuntu0.1~esm1
4 affected builds
Fixed in–
Ubuntu Pro 20.04 LTSbouncycastlepkg:deb/ubuntu/bouncycastle?arch=source&distro=esm-apps/focalOther threatsAffected
  • =1.61-1
  • =1.61-1ubuntu0.1~esm1
Fixed in–
Ubuntu Pro 22.04 LTSbouncycastlepkg:deb/ubuntu/bouncycastle?arch=source&distro=esm-apps/jammyOther threatsAffected
  • 1.68-2 – 1.68-5ubuntu0.1~esm1
4 affected builds
Fixed in–
Ubuntu Pro 24.04 LTSbouncycastlepkg:deb/ubuntu/bouncycastle?arch=source&distro=esm-apps/nobleOther threatsAffected
  • =1.72-2
  • =1.77-1
  • =1.77-1ubuntu0.1~esm1
Fixed in–
Ubuntu 26.10bouncycastlepkg:deb/ubuntu/bouncycastle?arch=source&distro=stonkingOther threatsAffected
  • =1.80-3
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

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