TI-2026-65847 Aliases CVE-2026-63572 GHSA-v54c-wxx6-mjh6

Unbounded MAC and bag-decryption iteration counts when loading PKCS#12 files

LOW 31CWE-770Published 2026-10-02 · Updated 2026-10-02

Key facts

Attack vector: Network
Privileges required: None
User interaction: Passive
Attack complexity: Low
Attack requirements: None
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-770.

Summary

Allocation of resources without limits in PKCS#12 keystore loading (Pkcs12Store.Load) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows an attacker who can supply a PKCS#12 (PFX) file to cause a denial of service through CPU exhaustion via an iteration count close to 2^31 in the file's MacData or in the PBE parameters of an encrypted SafeContents or shrouded key bag, because the counts are taken from the file without an upper bound and the key derivation runs before the MAC or the password can be checked. A zero or negative count is covered by CVE-2026-63575. Pkcs12Utilities.ConvertToDefiniteLength is also affected.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00376 31st percentileScored 2026-11-07

Fix Fixed bc-csharp (Legion of the Bouncy Castle Inc.): 2.7.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Legion of the Bouncy Castle Inc.	bc-csharp	before 2.7.0	2.7.0	Patch available	CNA

bc-csharp VendorLegion of the Bouncy Castle Inc. Affected before 2.7.0 Fixed in 2.7.0 Patch available CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:bouncycastle:bc-csharp::::::::	before 2.7.0	Vulnerable	Legion of the Bouncy Castle Inc.

cpe:2.3:a:bouncycastle:bc-csharp:*:*:*:*:*:*:*:* Versions before 2.7.0 Vulnerable ·Legion of the Bouncy Castle Inc.

Remediation

Fix · CNA bc-csharp (Legion of the Bouncy Castle Inc.) Fixed in 2.7.0

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

Release · 2026-10-02
Legion of the Bouncy Castle bc-csharp 2.7.0
21 records Highest priority Priority MEDIUM 8 MEDIUM, 13 LOW
Other records, highest priority first
- TI-2026-65844 MTI/A0 DHAgreement does not validate the peer's ephemeral valuePriority MEDIUM 47
- TI-2026-66020 Unbounded HSS public key level count allows huge array allocation during signature verificationPriority MEDIUM 44
- TI-2026-66017 Unbounded ASN.1 nesting depth causes process-terminating stack overflowPriority MEDIUM 44
Show all 21 records →

Timeline

2026-10-02 Threatist record created from CVE-2026-63572
2026-10-03 Alias added: GHSA-v54c-wxx6-mjh6
2026-10-28 CVSS score added · NVD

References

Patch 6

TI-2026-65844 MTI/A0 DHAgreement does not validate the peer's ephemeral value CVSS 4.0CRITICAL 9.1
TI-2026-66020 Unbounded HSS public key level count allows huge array allocation during signature verification CVSS 4.0HIGH 8.7
TI-2026-66017 Unbounded ASN.1 nesting depth causes process-terminating stack overflow CVSS 4.0HIGH 8.7
TI-2026-65849 Unbounded allocation from OpenPGP signature and user attribute subpacket lengths CVSS 4.0HIGH 8.7
TI-2026-65843 Unbounded CMP/CRMF password-based MAC iteration count allows CPU exhaustion CVSS 4.0HIGH 8.7
TI-2026-65841 DTLS handshake reassembler allocates buffer from unchecked 24-bit length CVSS 4.0HIGH 8.7

See all 21 →

Sources

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