CVE-2026-13586Network attack vector

Service stall via unbounded PKCS#12 KDF iterations

Published Aug 3, 2026 · Updated Aug 3, 2026

Unbounded KDF work in Bouncy Castle Java before 1.85 allows attackers to stall PKCS#12-loading threads with a crafted file. PKCS12KeyStoreSpi and PKCS12PBMAC1KeyStoreSpi use file-supplied iteration counts directly when deriving integrity-MAC and bag-decryption keys, without an upper bound. Reachability requires an application to open an untrusted keystore and also affects Java LTS before 2.73.12 and FIPS before 1.0.2.7, 2.0.2, and 2.1.3 in their respective release series; a tiny file can occupy the loading thread before password or integrity rejection.

CVSS severity5.3

Medium

EPSS probability0.35%

Next 30 days · Sep 16, 2026

Known exploitationUnconfirmed

Based on sourced intelligence

Hinoki checkNot available

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Summary

What happened

The record

CVE: CVE-2026-13586
Published: Aug 3, 2026
Updated: Aug 3, 2026

Vendor: Legion of the Bouncy Castle Inc.
Product: Bouncy Castle Java
Classifications: CWE-770, T1499.004

Attack vector: network
Privileges: unauthenticated

Timeline

How it unfolded

Aug 3, 2026CVE publishedPublication date reported by the CVE source.
Aug 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.

Affected versionversion=0 <1.85

What conditions does exploitation require?

Attack vectornetwork

Required privilegesunauthenticated

What is affected?

Legion of the Bouncy Castle Inc. · Bouncy Castle Javaversion=0 <1.85

Legion of the Bouncy Castle Inc. · Bouncy Castle FIPS Java APIversion=1.0.0 <1.0.2.7; version=2.0.0 <2.0.2; version=2.1.0 <2.1.3

Legion of the Bouncy Castle Inc. · Bouncy Castle Java LTSversion=2.73.0 <2.73.12

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

5.3Amazon LinuxCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

5.3Legion of the Bouncy Castle Inc.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

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.

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

No observations available

Sep 9, 2026Sep 15, 2026

Latest reporting daySep 15, 2026

Latest daily unique IPsUnavailable

Prior 30-day averageUnavailable

SourceShadowserver honeypots (KEV)

Vectornetwork

Privilegesunauthenticated

Known exploitationUnconfirmed

Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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