CVE-2026-17508— Password-based KDF cost parameters honoured unbounded from untrusted input across the remaining PBE entry points
Quick assessment
Affected
Legion of the Bouncy Castle Inc. BC-JAVA
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
在 Bouncy Castle for Java 1.86 之前的版本中，多个基于密码的密钥派生函数（KDF）入口点使用了来自不受信任输入的成本参数来运行 KDF，且未对这些参数进行限制。因此，一个小的输入就可能强制执行任意量的计算工作，以至于在任何密码或完整性检查能够拒绝该输入之前，系统已经完成了大量工作。 受影响的入口包括： 1. RFC 9579 PBMAC1 MAC 计算器构建器：这些构建器直接从 中获取 PBKDF2 迭代计数和派生密钥长度，而未对这些值加以限制。具体涉及 和通过 调用的 。 2. PKC
Possible ATT&CK Techniques 1 AI
T1496 · Resource HijackingAffected Version Matrix 7
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Legion of the Bouncy Castle Inc. | BC-FJA | 1.0.0< 1.0.13 |
affected |
2.0.0< 2.0.13 |
affected | ||
2.1.0< 2.1.13 |
affected | ||
| Legion of the Bouncy Castle Inc. | BC-JAVA | < 1.86 |
affected |
< 1.86 |
affected | ||
| Legion of the Bouncy Castle Inc. | BC-LTS-JAVA | 2.73.0< 2.73.13 |
affected |
2.73.0< 2.73.13 |
affected |
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I. Basic Information for CVE-2026-17508
Vulnerability Information
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Vulnerability Title
Password-based KDF cost parameters honoured unbounded from untrusted input across the remaining PBE entry points
Source: CVE Program / CVE List V5
Vulnerability 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).
Source: CVE Program / CVE List V5
CVSS Information
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
Source: CVE Program / CVE List V5
Vulnerability Type
不加限制或调节的资源分配
Source: CVE Program / CVE List V5
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| Legion of the Bouncy Castle Inc. | BC-JAVA | 0 ~ 1.86 | - |
|
| Legion of the Bouncy Castle Inc. | BC-JAVA | 0 ~ 1.86 | - |
|
| Legion of the Bouncy Castle Inc. | BC-LTS-JAVA | 2.73.0 ~ 2.73.13 | - |
|
| Legion of the Bouncy Castle Inc. | BC-LTS-JAVA | 2.73.0 ~ 2.73.13 | - |
|
| Legion of the Bouncy Castle Inc. | BC-FJA | 1.0.0 ~ 1.0.13 | - |
|
II. Public POCs for CVE-2026-17508
| # | POC Description | Source Link | Shenlong Link |
|---|
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Patches & Fixes for CVE-2026-17508 (6)
News Coverage for CVE-2026-17508 (1)
-
🔗 CVE‐2026‐17508 · bcgit/bc-java Wiki · GitHub vendor-advisory
Same Patch Batch · Legion of the Bouncy Castle Inc. · 2026-10-02 · 24 CVEs total
| CVE-2026-63569 | 9.1 CRITICAL | MTI/A0 DHAgreement does not validate the peer's ephemeral value |
| CVE-2026-63571 | 8.7 HIGH | Attribute certificate path validation does not verify the attribute certificate's signatur |
| CVE-2026-63566 | 8.7 HIGH | DTLS handshake reassembler allocates buffer from unchecked 24-bit length |
| CVE-2026-63574 | 8.7 HIGH | Unbounded allocation from OpenPGP signature and user attribute subpacket lengths |
| CVE-2026-63568 | 8.7 HIGH | Unbounded CMP/CRMF password-based MAC iteration count allows CPU exhaustion |
| CVE-2026-103600 | 8.7 HIGH | Unbounded ASN.1 nesting depth causes process-terminating stack overflow |
| CVE-2026-103604 | 8.7 HIGH | Quadratic-time escaping when converting X.509 distinguished names to strings |
| CVE-2026-103603 | 8.7 HIGH | Unbounded HSS public key level count allows huge array allocation during signature verific |
| CVE-2026-16000 | 8.7 HIGH | KCcmBlockCipher (DSTU 7624 CCM) tag not bound to nonce when no associated data is used |
| CVE-2026-17507 | 8.7 HIGH | MLS membership checks compare a uint32 leaf_index as signed, admitting an out-of-range sen |
| CVE-2026-103602 | 8.2 HIGH | Name constraints bypass via trailing dot in rfc822Name, dNSName and URI hosts |
| CVE-2026-18036 | 8.2 HIGH | NTRU leaks private key information by reducing secret values with a non-constant-time inte |
| CVE-2026-63577 | 8.2 HIGH | Name Constraints bypass: directoryName constraint matched at any position in the DN instea |
| CVE-2026-63576 | 8.2 HIGH | URI name constraints checked against a mis-parsed host |
| CVE-2026-63573 | 8.2 HIGH | Bleichenbacher padding oracle in CMS RSA PKCS#1 v1.5 key-transport unwrap |
| CVE-2026-103601 | 8.2 HIGH | CcmBlockCipher and KCcmBlockCipher leave unverified plaintext in the output buffer after a |
| CVE-2026-63567 | 8.2 HIGH | IesEngine block-cipher mode checks padding before MAC (CBC padding oracle) |
| CVE-2026-15999 | 8.2 HIGH | AES-CCM decryption accepts zero or out-of-range tag length, bypassing authentication |
| CVE-2026-16001 | 8.2 HIGH | IesEngine stream-mode MAC forgery via length-dependent KDF split |
| CVE-2026-63578 | 7.1 HIGH | Unbounded PBE iteration count when decrypting PKCS#8 private keys |
Showing top 20 of 24 CVEs. View all on vendor page → →
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V. Comments for CVE-2026-17508
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