CVE-2026-33753
6.2 · MEDIUMOverview
CVE-2026-33753 is a medium-severity vulnerability affecting trailofbits rfc3161-client. It was published on April 8, 2026 and has a CVSS 3.1 base score of 6.2 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 6.2, rated MEDIUM. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.
Technical Description
rfc3161-client is a Python library implementing the Time-Stamp Protocol (TSP) described in RFC 3161. Prior to 1.0.6, an Authorization Bypass vulnerability in rfc3161-client's signature verification allows any attacker to impersonate a trusted TimeStamping Authority (TSA). By exploiting a logic flaw in how the library extracts the leaf certificate from an unordered PKCS#7 bag of certificates, an attacker can append a spoofed certificate matching the target common_name and Extended Key Usage (EKU) requirements. This tricks the library into verifying these authorization rules against the forged certificate while validating the cryptographic signature against an actual trusted TSA (such as FreeTSA), thereby bypassing the intended TSA authorization pinning entirely. This vulnerability is fixed in 1.0.6.
Remediation
Check the references section for vendor advisories and patches from trailofbits. Update rfc3161-client to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| trailofbits | rfc3161-client | >= 0, < 1.0.6 | Affected |
Frequently Asked Questions
What is CVE-2026-33753?
CVE-2026-33753 is a medium-severity vulnerability affecting trailofbits rfc3161-client. It was published on April 8, 2026 and has a CVSS 3.1 base score of 6.2 (MEDIUM).
How severe is CVE-2026-33753?
This vulnerability has a CVSS 3.1 base score of 6.2, rated MEDIUM. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-33753?
Check the references section for vendor advisories and patches from trailofbits. Update rfc3161-client to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-33753?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-33753 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
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