High severity · published Oct 2, 2026
CVE-2026-63572
Unbounded MAC and bag-decryption iteration counts when loading PKCS#12 files
7.5
CVSS
0.3%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 26% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
BC
bc-csharp · Legion of the Bouncy Castle Inc.
before 2.7.0 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-63572
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-63572
vendor-advisory
https://github.com/bcgit/bc-csharp/wiki/CVE-2026-63572
patch
https://github.com/bcgit/bc-csharp/commit/7c0ed15f9783c9595b1a53f3900136461fd944f4
patch
https://github.com/bcgit/bc-csharp/commit/c00fc018fca89c077c64dd2a2a2eb00ae7d97241
patch
https://github.com/bcgit/bc-csharp/commit/54ea0b179ee627027829b44c45d6dd32e575bd67
patch
https://github.com/bcgit/bc-csharp/commit/34a7c05f719c91c024f285c6b420d3c00f8019dd
patch
https://github.com/bcgit/bc-csharp/commit/b57165ecb7790ecea08273b219d52d80c12990e4
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