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

Quick assessment

Affected
Legion of the Bouncy Castle Inc. bc-csharp
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

在 Legion of the Bouncy Castle Inc. 的 bc-csharp 项目（2.7.0 版本之前）中，Pkcs12Store.GetCertificateChain 方法存在一个循环退出条件不可达的漏洞。该漏洞允许攻击者通过向应用程序提供一个精心构造的 PKCS#12 文件，并在该文件被加载后请求获取密钥条目对应的证书链，从而引发拒绝服务（DoS）攻击。具体表现为：该调用永远不会返回，持续消耗 CPU 和内存资源，最终可能因内存溢出（OutOfMemoryException）而失败。其根本原

CVSS 7.1 · High EPSS 0.21% · P11

Affected Version Matrix 1

VendorProduct Version RangeStatus
Legion of the Bouncy Castle Inc. bc-csharp < 2.7.0 affected
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I. Basic Information for CVE-2026-63570

Vulnerability Information
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Vulnerability Title
Pkcs12Store.GetCertificateChain loops forever on cyclic issuer links
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
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
Source: CVE Program / CVE List V5
Vulnerability Type
不可达退出条件的循环(无限循环)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Legion of the Bouncy Castle Inc. bc-csharp 0 ~ 2.7.0 -

II. Public POCs for CVE-2026-63570

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III. Intelligence Information for CVE-2026-63570

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Patches & Fixes for CVE-2026-63570 (1)

Vendor Advisories for CVE-2026-63570 (1)

Same Patch Batch · Legion of the Bouncy Castle Inc. · 2026-10-02 · 24 CVEs total

CVE-2026-63569 9.1 CRITICAL MTI/A0 DHAgreement does not validate the peer's ephemeral value
CVE-2026-63571 8.7 HIGH Attribute certificate path validation does not verify the attribute certificate's signatur
CVE-2026-63566 8.7 HIGH DTLS handshake reassembler allocates buffer from unchecked 24-bit length
CVE-2026-63574 8.7 HIGH Unbounded allocation from OpenPGP signature and user attribute subpacket lengths
CVE-2026-63568 8.7 HIGH Unbounded CMP/CRMF password-based MAC iteration count allows CPU exhaustion
CVE-2026-103600 8.7 HIGH Unbounded ASN.1 nesting depth causes process-terminating stack overflow
CVE-2026-103604 8.7 HIGH Quadratic-time escaping when converting X.509 distinguished names to strings
CVE-2026-103603 8.7 HIGH Unbounded HSS public key level count allows huge array allocation during signature verific
CVE-2026-16000 8.7 HIGH KCcmBlockCipher (DSTU 7624 CCM) tag not bound to nonce when no associated data is used
CVE-2026-17507 8.7 HIGH MLS membership checks compare a uint32 leaf_index as signed, admitting an out-of-range sen
CVE-2026-103602 8.2 HIGH Name constraints bypass via trailing dot in rfc822Name, dNSName and URI hosts
CVE-2026-18036 8.2 HIGH NTRU leaks private key information by reducing secret values with a non-constant-time inte
CVE-2026-63577 8.2 HIGH Name Constraints bypass: directoryName constraint matched at any position in the DN instea
CVE-2026-63576 8.2 HIGH URI name constraints checked against a mis-parsed host
CVE-2026-63573 8.2 HIGH Bleichenbacher padding oracle in CMS RSA PKCS#1 v1.5 key-transport unwrap
CVE-2026-103601 8.2 HIGH CcmBlockCipher and KCcmBlockCipher leave unverified plaintext in the output buffer after a
CVE-2026-63567 8.2 HIGH IesEngine block-cipher mode checks padding before MAC (CBC padding oracle)
CVE-2026-15999 8.2 HIGH AES-CCM decryption accepts zero or out-of-range tag length, bypassing authentication
CVE-2026-16001 8.2 HIGH IesEngine stream-mode MAC forgery via length-dependent KDF split
CVE-2026-63578 7.1 HIGH Unbounded PBE iteration count when decrypting PKCS#8 private keys

Showing top 20 of 24 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: bc-csharp
Same vendor: Legion of the Bouncy Castle Inc.
Same weakness: CWE-835

V. Comments for CVE-2026-63570

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