---
title: "CVE-2026-85515: Bouncy Castle Java - Broken Authentication"
description: "Bouncy Castle for Java < 1.86 contains a missing truncation error caused by improper handling of truncated OpenPGP encrypted messages in SEIPD version 1 and AEAD paths, letting attackers bypass integrity checks and obtain altered plaintext without error, exploit requires truncated message input."
url: https://panop.io/threat-heartbeat/CVE-2026-85515/
---

# CVE-2026-85515 Bouncy Castle Java - Broken Authentication

Bouncy Castle for Java < 1.86 contains a missing truncation error caused by improper handling of truncated OpenPGP encrypted messages in SEIPD version 1 and AEAD paths, letting attackers bypass integrity checks and obtain altered plaintext without error, exploit requires truncated message input.

CVSS base score 8.2 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.16% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-85515)

## Details

Type

Broken Authentication

Impact

Data Tampering, Information Disclosure

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Amber

Published

3 October 2026

Updated

15 October 2026

Weakness

[CWE-345](https://cwe.mitre.org/data/definitions/345.html)

## Vendor fix

Update to Bouncy Castle for Java 1.86 or later, or apply patches in LTS 2.73.13 and FIPS bcpg-fips 1.0.14, 2.0.14.1, 2.1.14 or later versions.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-85515](https://nvd.nist.gov/vuln/detail/CVE-2026-85515)
- [https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9085515](https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9085515)
- [https://github.com/bcgit/bc-java/commit/ab7a235d1c20e3da28ce77167a96b5c14025efa7](https://github.com/bcgit/bc-java/commit/ab7a235d1c20e3da28ce77167a96b5c14025efa7)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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