Legion of the Bouncy Castle Bouncy Castle for Java up to 2.1.12 PBMAC1 MAC Calculator PKCS12PfxPdu.isMacValid resource consumption

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4.1	$0-$5k	0.87-

Summaryinfo

A vulnerability was found in Legion of the Bouncy Castle Bouncy Castle for Java, Bouncy Castle for Java LTS and Bouncy Castle for Java FIPS up to 1.85/2.73.12/1.0.12/2.0.12/2.1.12 and classified as problematic. This vulnerability affects the function PKCS12PfxPdu.isMacValid of the component PBMAC1 MAC Calculator/Scrypt Parameter Handler/PBKDF2 Provider/Bcrypt Round Count Reader. Such manipulation of the argument cost_parameters/iteration_count/derived_key_length/parallelization_parameter_p/cost_parameter_N/block_size_r leads to resource consumption. This vulnerability is documented as CVE-2026-17508. The attack can be executed remotely. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Legion of the Bouncy Castle Bouncy Castle for Java, Bouncy Castle for Java LTS and Bouncy Castle for Java FIPS up to 1.85/2.73.12/1.0.12/2.0.12/2.1.12. Affected by this issue is the function PKCS12PfxPdu.isMacValid of the component PBMAC1 MAC Calculator/Scrypt Parameter Handler/PBKDF2 Provider/Bcrypt Round Count Reader. The manipulation of the argument cost_parameters/iteration_count/derived_key_length/parallelization_parameter_p/cost_parameter_N/block_size_r with an unknown input leads to a resource consumption vulnerability. Using CWE to declare the problem leads to CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. Impacted is availability. CVE summarizes:

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).

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-17508 since 07/27/2026. The exploitation is known to be easy. The attack may be launched remotely. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 1.86, 2.73.13, 1.0.13, 2.0.13 or 2.1.13 eliminates this vulnerability.

The vulnerability is also documented in the databases at EUVD (EUVD-2026-91236) and CERT Bund (WID-SEC-2026-3713). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

• Open Source Bouncy Castle

Productinfo

Type

• Programming Language Software

Vendor

• Legion of the Bouncy Castle

Name

• Bouncy Castle for Java
• Bouncy Castle for Java FIPS
• Bouncy Castle for Java LTS

Version

• 1.0
• 1.0.0
• 1.0.1
• 1.0.2
• 1.0.3
• 1.0.4
• 1.0.5
• 1.0.6
• 1.0.7
• 1.0.8
• 1.0.9
• 1.0.10
• 1.0.11
• 1.0.12
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.16
• 1.17
• 1.18
• 1.19
• 1.20
• 1.21
• 1.22
• 1.23
• 1.24
• 1.25
• 1.26
• 1.27
• 1.28
• 1.29
• 1.30
• 1.31
• 1.32
• 1.33
• 1.34
• 1.35
• 1.36
• 1.37
• 1.38
• 1.39
• 1.40
• 1.41
• 1.42
• 1.43
• 1.44
• 1.45
• 1.46
• 1.47
• 1.48
• 1.49
• 1.50
• 1.51
• 1.52
• 1.53
• 1.54
• 1.55
• 1.56
• 1.57
• 1.58
• 1.59
• 1.60
• 1.61
• 1.62
• 1.63
• 1.64
• 1.65
• 1.66
• 1.67
• 1.68
• 1.69
• 1.70
• 1.71
• 1.72
• 1.73
• 1.74
• 1.75
• 1.76
• 1.77
• 1.78
• 1.79
• 1.80
• 1.81
• 1.82
• 1.83
• 1.84
• 1.85
• 2.0.0
• 2.0.1
• 2.0.2
• 2.0.3
• 2.0.4
• 2.0.5
• 2.0.6
• 2.0.7
• 2.0.8
• 2.0.9
• 2.0.10
• 2.0.11
• 2.0.12
• 2.1.0
• 2.1.1
• 2.1.2
• 2.1.3
• 2.1.4
• 2.1.5
• 2.1.6
• 2.1.7
• 2.1.8
• 2.1.9
• 2.1.10
• 2.1.11
• 2.1.12
• 2.73.0
• 2.73.1
• 2.73.2
• 2.73.3
• 2.73.4
• 2.73.5
• 2.73.6
• 2.73.7
• 2.73.8
• 2.73.9
• 2.73.10
• 2.73.11
• 2.73.12

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 4.3
VulDB Meta Temp Score: 4.1

VulDB Base Score: 4.3
VulDB Temp Score: 4.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Resource consumption
CWE: CWE-400 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Bouncy Castle for Java/Bouncy Castle for Java LTS/Bouncy Castle for Java FIPS 1.86/2.73.13/1.0.13/2.0.13/2.1.13

Timelineinfo

07/27/2026 CVE reserved
10/02/2026 +67 days Advisory disclosed
10/02/2026 +0 days VulDB entry created
10/02/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-17508 (🔒)
GCVE (CVE): GCVE-0-2026-17508
GCVE (VulDB): GCVE-100-412976
EUVD: 🔒
CERT Bund: WID-SEC-2026-3713 - Bouncy Castle: Mehrere Schwachstellen

Entryinfo

Created: 10/02/2026 09:53
Updated: 10/02/2026 20:34
Changes: 10/02/2026 09:53 (71), 10/02/2026 15:22 (7), 10/02/2026 20:34 (1)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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