Upstream information
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.SUSE information
Overall state of this security issue: Does not affect SUSE products
This issue is currently rated as having moderate severity.
| CVSS detail | CNA (GitHub) |
|---|---|
| Base Score | 6.2 |
| Vector | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
| Attack Vector | Local |
| Attack Complexity | Low |
| Privileges Required | None |
| User Interaction | None |
| Scope | Unchanged |
| Confidentiality Impact | None |
| Integrity Impact | High |
| Availability Impact | None |
| CVSSv3 Version | 3.1 |
SUSE Timeline for this CVE
CVE page created: Wed Apr 8 20:04:23 2026CVE page last modified: Thu Apr 9 16:51:54 2026