Description
In Bouncy Castle for Java before 1.86, the raw JCA provider's legacy PBES1 (PKCS#5 scheme 1) and PKCS#12 PBE families ran their password-based key derivation with an iteration count taken from untrusted input without bounding it, so a small input could dictate an arbitrary amount of work before anything could be verified. The AlgorithmParameters implementations (PKCS12PBE and its object identifier aliases, and PBKDF1) accepted any count from an encoded PKCS12PBEParams or PBEParameter, narrowing a value beyond the int range with intValue(), and every Cipher, Mac and SecretKeyFactory in these families derived with whatever count it was given, including one decoded by another provider's AlgorithmParameters, as when javax.crypto.EncryptedPrivateKeyInfo.getKeySpec() decrypts a PKCS#12 PBE-protected private key with BC. Both the parameter parse and the derivations now reject a negative or over-limit count under the org.bouncycastle.pbe.max_iteration_count property (default 10,000,000) that already bounded PBKDF2 (CVE-2026-17508), and the parse rejects a count beyond the int range rather than narrowing it. This issue also affects Bouncy Castle for Java LTS before 2.73.13.
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 |
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-2026-3726 Bouncy Castle für Java: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 11, 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