CVE-2026-63578Unbounded PBE iteration count when decrypting PKCS#8 private keys
Updated under an hour ago ()
Does this affect you?
It affects Legion of the Bouncy Castle Inc. bc-csharp. Add what you run to find out whether that includes you.
EPSS puts the chance of exploitation in the next 30 days at 0.33%, higher than 25% of scored CVEs.
Do this next
Free account, 1 product
Allocation of resources without limits in password-based private-key decryption (PbeUtilities.GenerateCipherParameters) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows an attacker who can supply an encrypted private key, such as a PKCS#8 EncryptedPrivateKeyInfo or "ENCRYPTED PRIVATE KEY" PEM file, to cause a denial of service through CPU exhaustion via an iteration count close to 2^31, because the count is taken from the unauthenticated algorithm parameters without an upper bound and the key derivation runs before the password or the data can be checked. PKCS#5 PBES1 and PBES2 (PBKDF2), the PKCS#12 PBE algorithms and CMS password recipients (CmsPbeKey) are affected. Loading PKCS#12 files with Pkcs12Store is covered by CVE-2026-63572, and a zero or negative count with the PKCS#12 algorithms by CVE-2026-63575.
- CVSS
- 7.1 HIGH (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- Weakness (CWE)
- CWE-770
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- 0.33% (percentile 25)
- Assigned by
- bcorg
- NVD analysis
- Undergoing Analysis
- Record last updated
- Oct 6, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Legion of the Bouncy Castle Inc. bc-csharp legion_of_the_bouncy_castle:bc_csharp (from the name) | before 2.7.0 | CNA record |
References
- https://github.com/bcgit/bc-csharp/wiki/CVE-2026-63578vendor-advisory
- https://github.com/bcgit/bc-csharp/commit/c00fc018fca89c077c64dd2a2a2eb00ae7d97241patch
- https://github.com/bcgit/bc-csharp/commit/54ea0b179ee627027829b44c45d6dd32e575bd67patch
- https://github.com/bcgit/bc-csharp/commit/7c0ed15f9783c9595b1a53f3900136461fd944f4patch
- https://github.com/bcgit/bc-csharp/commit/34a7c05f719c91c024f285c6b420d3c00f8019ddpatch
- https://github.com/bcgit/bc-csharp/commit/b57165ecb7790ecea08273b219d52d80c12990e4patch
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.