CVE-2026-85515Hinoki check available

Altered plaintext acceptance via swallowed truncation error

Published Oct 3, 2026 · Updated Oct 3, 2026

OpenPGP message truncation in Bouncy Castle Java before 1.86 allows attackers to pass crafted ciphertext without an integrity error. BCPGInputStream.nextPacketTag treats a missing-ciphertext EOF as normal packet exhaustion, preventing AEAD streams from reaching the final length tag and the high-level SEIPDv1 stream from running its modification detection check. The failure requires a specially aligned truncated message; LTS before 2.73.13 and affected FIPS bcpg-fips branches have only the AEAD route, which releases authenticated chunks but can silently discard following packets.

CVSS severityUnavailable
Unscored
EPSS probability0.16%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

OpenPGP message truncation in Bouncy Castle Java before 1.86 allows attackers to pass crafted ciphertext without an integrity error. BCPGInputStream.nextPacketTag treats a missing-ciphertext EOF as normal packet exhaustion, preventing AEAD streams from reaching the final length tag and the high-level SEIPDv1 stream from running its modification detection check. The failure requires a specially aligned truncated message; LTS before 2.73.13 and affected FIPS bcpg-fips branches have only the AEAD route, which releases authenticated chunks but can silently discard following packets.

The record

CVE
CVE-2026-85515
Published
Oct 3, 2026
Updated
Oct 3, 2026
Vendor
Legion of the Bouncy Castle Inc.
Product
Bouncy Castle Java
Classifications
Unavailable
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Oct 3, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 3, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.74 <1.86

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

Legion of the Bouncy Castle Inc. · Bouncy Castle Javaversion=1.74 <1.86
Legion of the Bouncy Castle Inc. · Bouncy Castle FIPS Java APIversion=1.0.7 <1.0.14; version=2.0.7 <2.0.14.1; version=2.1.0 <2.1.14
Legion of the Bouncy Castle Inc. · Bouncy Castle Java LTSversion=2.73.0 <2.73.13

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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