CVE-2026-102271
Description
A flaw was found in PyJWT. The library fails to identify asymmetric public keys supplied in Distinguished Encoding Rules (DER) format, inadvertently treating the public data as a shared secret in Hash-based Message Authentication Code (HMAC) operations. If an application supports both asymmetric and symmetric signing algorithms, a remote attacker knowing the public key can exploit this flaw to forge valid authentication tokens and bypass access controls.
Statement
This vulnerability is rated as Important because an attacker can forge valid JSON Web Tokens and bypass authentication mechanisms if public cryptographic keys are mistakenly treated as shared secrets. Exploitation requires a specific application scenario where both asymmetric and HMAC algorithms are concurrently permitted during signature verification and public keys are provided in raw DER binary format. Typical Red Hat product integrations do not employ this vulnerable algorithm combination or key encoding by default, which restricts the overall attack surface in standard production environments.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.4 | N/A | 7.4 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Understanding the Weakness (CWE)
Access Control,Integrity,Confidentiality
Technical Impact: Gain Privileges or Assume Identity; Modify Application Data; Execute Unauthorized Code or Commands
An attacker could gain access to sensitive data and possibly execute unauthorized code.
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