High 7.1Published Oct 2, 2026

CVE-2026-63570Pkcs12Store.GetCertificateChain loops forever on cyclic issuer links

Updated under an hour ago (2026-10-19 09:00 UTC)

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 0.21%, higher than 11% of scored CVEs.

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Every CVE for Legion of the Bouncy Castle Inc. bc-csharp

Exploited in the last 30 days

Loop with unreachable exit condition in Pkcs12Store.GetCertificateChain in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows an attacker who can supply a crafted PKCS#12 file to an application that loads it and requests a key entry's certificate chain to cause a denial of service, in which the call never returns and consumes CPU and memory until an OutOfMemoryException, via certificates whose issuer links form a cycle, for example two certificates whose AuthorityKeyIdentifier extensions each identify the other's public key. This happens because the chain-building loop stops only when no issuer is found or a certificate links to itself, and keeps no record of certificates already visited. The key-identifier links are followed without checking signatures.

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-835
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): 0.21% (percentile 11)
Assigned by: bcorg
NVD analysis: Undergoing Analysis
Record last updated: Oct 2, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

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-2026-63570vendor-advisory
https://github.com/bcgit/bc-csharp/commit/1b8fad04df4953230c9951c57678ee45c8aead85patch

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.