# CVE-2026-17508: bouncycastle: This update for bouncycastle fixes the following issues:  - CVE-2026-17507: negative signed leaf_index values from un...

CVE-2026-17508 is fixed in bouncycastle on 1 platform, first by DEBIAN-CVE-2026-17508, released October 3, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-17508
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0042
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 2, 2026

## Description

This update for bouncycastle fixes the following issues:  - CVE-2026-17507: negative signed leaf_index values from unsigned wire encodings can cause heap exhaustion   (bsc#1284075). - CVE-2026-17508: unbounded KDF iteration and memory parameters can cause resource exhaustion (bsc#1284073). - CVE-2026-18036: variable-time modulo and division operations in NTRU implementation can allow timing side-channel   attacks (bsc#1284065). - CVE-2026-18040: table lookups and variable-time duplicate scanning in HQC can cause cache side-channel leaks   (bsc#1284205). - CVE-2026-71885: unbound X.509 certificates in MLS LeafNode verification can cause identity impersonation and group   message interception (bsc#1284165). - CVE-2026-71886: unvalidated CERTIFY_OTHER flags in OpenPGP subkeys can cause unauthorized trust delegations and   identity spoofing (bsc#1284212). - CVE-2026-71887: missing primary key back-signature validation on subkeys can cause signature misattribution and trust   context spoofing (bsc#1284213). - CVE-2026-71888: disagreement between digestAlgorithm and authAttrs in CMS parsing can cause unauthenticated attribute   injection (bsc#1284215). - CVE-2026-71889: skipped leaf certificate evaluation in checkNameConstraints can cause X.509 name constraint bypasses   (bsc#1284218). - CVE-2026-71890: unbounded Remove proposals in external MLS commits can cause arbitrary group member eviction and   session takeover (bsc#1284219). - CVE-2026-71891: forged ECPoint curves in BLS12-381 key validation can cause aggregate signature verification bypasses   (bsc#1284220). - CVE-2026-71892: type mismatch in CMS key-transport validation can cause key-size enforcement bypasses for HKDF-derived   content keys (bsc#1284221). - CVE-2026-85515: laundered EOF exceptions in OpenPGP message stream processing can cause unregistered truncation errors   and integrity check bypasses (bsc#1284222). - CVE-2026-97873: unbounded iteration counts in legacy PBES1 and PKCS#12 PBE implementations can cause resource   exhaustion (bsc#1284224).  Changes for bouncycastle:  - Updated to version 1.86.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | bouncycastle Debian 14 | 1.86-1 | [DEBIAN-CVE-2026-17508](https://patchblox.com/security/data/fix/linux/debian-cve-2026-17508.md) | Oct 3, 2026 |
| Linux | bouncycastle opensuse-leap 16.0 | 1.86-160000.1.1 | [OPENSUSE-SU-2026:22169-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22169-1.md) | Nov 7, 2026 |
| Linux | bouncycastle sles 15.6 | 1.86-150200.3.41.1 | [SUSE-SU-2026:4797-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4797-1.md) | Nov 7, 2026 |
| Linux | bouncycastle sles 15.7 | 1.86-150200.3.41.1 | [SUSE-SU-2026:4797-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4797-1.md) | Nov 7, 2026 |
| Linux | bouncycastle sles 16.0 | 1.86-160000.1.1 | [SUSE-SU-2026:24461-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24461-1.md) | Nov 7, 2026 |

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Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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