CVE-2026-103604

HIGHCVSS 8.7/10EPSS 0.26%

Last modified

CVE-2026-103604 is a high-severity vulnerability rated 8.7/10 on the CVSS scale. Inefficient algorithmic complexity in X.509 distinguished name string conversion (X509Name.ToString and IetfUtilities.ValueToString) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote unauthenticated attacker to cause a denial of service through CPU exhaustion via a certificate, CRL, certification request or other structure whose name contains a long attribute value made up of characters that must be escaped, such as commas, or of leading or trailing spaces, because each escaping backslash was inserted into the buffer being scanned, so the work grew quadratically with the length of the value. EPSS estimates a 0.26% chance of exploitation in the next 30 days.

Description

Inefficient algorithmic complexity in X.509 distinguished name string conversion (X509Name.ToString and IetfUtilities.ValueToString) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote unauthenticated attacker to cause a denial of service through CPU exhaustion via a certificate, CRL, certification request or other structure whose name contains a long attribute value made up of characters that must be escaped, such as commas, or of leading or trailing spaces, because each escaping backslash was inserted into the buffer being scanned, so the work grew quadratically with the length of the value. Applications are exposed when they convert such a name to a string, for example to log or display it, or compare it with IetfUtilities.RdnAreEqual, as PKIX path validation does for directoryName name constraints.

Metrics

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
Legion of the Bouncy Castle Inc.bc-csharp< 2.7.0

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-103604?
Inefficient algorithmic complexity in X.509 distinguished name string conversion (X509Name.ToString and IetfUtilities.ValueToString) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote unauthenticated attacker to cause a denial of service through CPU exhaustion via a certificate, CRL, certification request or other structure whose name contains a long attribute value made up of characters that must be escaped, such as commas, or of leading or trailing spaces, because each escaping backslash was inserted into the buffer being scanned, so the work grew quadratically with the length of the value. Applications are exposed when they convert such a name to a string, for example to log or display it, or compare it with IetfUtilities.RdnAreEqual, as PKIX path validation does for directoryName name constraints.
How severe is CVE-2026-103604?
CVE-2026-103604 has a CVSS score of 8.7/10 (HIGH severity). The EPSS model estimates a 0.26% probability of exploitation in the next 30 days.
How do I fix CVE-2026-103604?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST