Timing Attack Affecting authlib package, versions [,1.6.9)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PYTHON-AUTHLIB-15674451
- published17 Mar 2026
- disclosed16 Mar 2026
- creditJay Neiva, Pr00fOf3xpl0it
Introduced: 16 Mar 2026
CVE-2026-28490 (opens in a new tab)How to fix?
Upgrade authlib to version 1.6.9 or higher.
Overview
authlib is a library in building OAuth and OpenID Connect servers.
Affected versions of this package are vulnerable to Timing Attack via the unwrap length check in jwe_algs.py. An attacker can recover the CEK and decrypt or forge JWE tokens by sending malformed RSA1_5 ciphertexts and observing the different ValueError("Invalid "cek" length") versus InvalidTag responses.