Description
In Bouncy Castle for Java before 1.86, several password-based key derivation entry points ran the KDF with cost parameters taken from the untrusted input being processed, without bounding them, so a small input could dictate an arbitrary amount of work before any password or integrity check could reject it. The affected paths are the RFC 9579 PBMAC1 MAC calculator builders, which took the PBKDF2 iteration count and derived-key length straight out of PBMAC1Params (JcePBMac1CalculatorBuilder, and PKCS12PBEUtils.createPBMac1Calculator reached from PKCS12PfxPdu.isMacValid); the scrypt parallelization parameter p in the PKCS#8 and PKCS#12 cost guards, which bounded only the cost parameter N and the block size r even though the scratch buffer scales with r times p, so the configured memory ceiling could be evaded entirely; the raw JCA PBKDF2 provider (org.bouncycastle.jcajce.provider.symmetric.PBEPBKDF2); and the bcrypt round count read from an encrypted OpenSSH v1 private key's own kdfoptions. Each now bounds the parameter before deriving, in line with the caps already applied elsewhere in the tree, with the OpenSSH round count configurable through the new org.bouncycastle.openssh.max_rounds property. This completes the bounding begun in 1.85 for the PKCS#8 / PBES2 decryptors (CVE-2026-15055). This issue also affects Bouncy Castle for Java LTS before 2.73.13, and Bouncy Castle for Java FIPS (BC-FJA) before bcpkix-fips 1.0.13 (1.0.X series), 2.0.13 (2.0.X series) and 2.1.13 (2.1.X series).
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Legion of the Bouncy Castle | BC-JAVA | < 1.86 | 1.86 |
| Legion of the Bouncy Castle | BC-LTS-JAVA | 2.73.0 – < 2.73.13 | 2.73.13 |
| Legion of the Bouncy Castle | BC-FJA | 1.0.0 – < 1.0.13, 2.0.0 – < 2.0.13, 2.1.0 – < 2.1.13 | 1.0.13 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | bouncycastle | 1.86-1 | — |
| Debian 13 | bouncycastle | No fix yet | — |
| Debian 12 | bouncycastle | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | bouncycastle | No fix yet | — |
| Ubuntu 26.04 LTS | bouncycastle | No fix yet | — |
Show 5 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 24.04 LTS | bouncycastle | No fix yet | — |
| Ubuntu Pro 22.04 LTS | bouncycastle | No fix yet | — |
| Ubuntu Pro 20.04 LTS | bouncycastle | No fix yet | — |
| Ubuntu Pro 18.04 LTS | bouncycastle | No fix yet | — |
| Ubuntu Pro 16.04 LTS | bouncycastle | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | bouncycastle | 1.86-150200.3.41.1 | SUSE-SU-2026:4797-1 |
| SLES 15 SP6 | bouncycastle | 1.86-150200.3.41.1 | SUSE-SU-2026:4797-1 |
| SLES 15 SP5 | bouncycastle | 1.86-150200.3.41.1 | SUSE-SU-2026:4797-1 |
| SLES 15 SP4 | bouncycastle | 1.86-150200.3.41.1 | SUSE-SU-2026:4797-1 |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | bouncycastle | 1.86-160000.1.1 | SUSE-SU-2026:24461-1 |
| SLES for SAP 15 SP6 | bouncycastle | 1.86-150200.3.41.1 | SUSE-SU-2026:4797-1 |
| SLES for SAP 15 SP5 | bouncycastle | 1.86-150200.3.41.1 | SUSE-SU-2026:4797-1 |
| SLES for SAP 15 SP4 | bouncycastle | 1.86-150200.3.41.1 | SUSE-SU-2026:4797-1 |
| SLES 16.0 | bouncycastle | 1.86-160000.1.1 | SUSE-SU-2026:24461-1 |
| SLE HPC 15 SP5 | bouncycastle | 1.86-150200.3.41.1 | SUSE-SU-2026:4797-1 |
| SLE HPC 15 SP4 | bouncycastle | 1.86-150200.3.41.1 | SUSE-SU-2026:4797-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | bouncycastle | 1.86-1.1 | openSUSE-SU-2026:12090-1 |
| openSUSE Leap 16.0 | bouncycastle | 1.86-160000.1.1 | openSUSE-SU-2026:22169-1 |
Advisories 5
- WID-SEC-2026-3713 Bouncy Castle: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 9, 2026
- SUSE-SU-2026:24461-1 Security update for bouncycastle SUSE / openSUSE Security Updates · Nov 4, 2026
- openSUSE-SU-2026:22169-1 Security update for bouncycastle SUSE / openSUSE Security Updates · Nov 1, 2026
- SUSE-SU-2026:4797-1 Security update for bouncycastle SUSE / openSUSE Security Updates · Oct 21, 2026
- openSUSE-SU-2026:12090-1 bouncycastle-1.86-1.1 on GA media SUSE / openSUSE Security Updates · Oct 10, 2026
References
- https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9017508 vendor-advisory
- https://github.com/bcgit/bc-java/commit/882fdab53f6c4c150a5d6a4e6ef1fc05d382385a patch
- https://github.com/bcgit/bc-java/commit/442393bf187c914b1e66fbed4fab532a1fe06c6a patch
- https://github.com/bcgit/bc-java/commit/20ed9e203caec91d25cd386ceb6d364e9b068f67 patch
- https://github.com/bcgit/bc-java/commit/766a31026ac24ed3c6cad8662058ba450c338da1 patch
- https://github.com/bcgit/bc-java/commit/e72bc0681ff4227fced912ef7394daf7b7d57bb3 patch
- https://github.com/bcgit/bc-java/commit/480d878aa6f7dc8b20403064f304bbe0decbbb1a patch