Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.9, a cryptographic padding oracle vulnerability was identified in the Authlib Python library concerning the implementation of the JSON Web Encryption (JWE) RSA1_5 key management algorithm. Authlib registers RSA1_5 in its default algorithm registry without requiring explicit opt-in, and actively destroys the constant-time Bleichenbacher mitigation that the underlying cryptography library implements correctly. This issue has been patched in version 1.6.9.
CVE-2026-28490
This medium-severity CVE scores 6.5 under NVD CVSS v3. EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- Lower severity and no public exploit yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 6.5
- EG Score
- 6.5(low)
- EG Risk
- 34(Track)EG Risk 34/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity65% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
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- EPSS %ILE
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- KEV
- Not listed
Published
March 16, 2026
Last Modified
June 17, 2026
References (3)
- security-advisories@githubhttps://github.com/authlib/authlib/commit/48b345f29f6c459f11c6a40162b6c0b742ef2e22
- security-advisories@githubhttps://github.com/authlib/authlib/releases/tag/v1.6.9
- security-advisories@githubhttps://github.com/authlib/authlib/security/advisories/GHSA-7432-952r-cw78
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 2× in last 7d / 2× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-27 14:41 UTCEG score recompute
- 2026-07-27 14:27 UTCOSV refresh
Related CVEs(same CWE)
Same CWE
10 shownCWE-327 · CWE-203
- CVE-2015-2808NVD 3.7EG 10.0EPSS p99CRITICAL
- CVE-2015-9235EG 9.8EPSS p95CRITICAL
- CVE-2017-17878EG 9.8CRITICAL
- CVE-2017-17717EG 9.8CRITICAL
- CVE-2012-4449EG 9.8CRITICAL
- CVE-2014-9969EG 9.8CRITICAL
- CVE-2014-8687EG 9.8EPSS p99CRITICAL
- CVE-2017-4917EG 9.8CRITICAL
- CVE-2016-6602EG 9.8EPSS p99CRITICAL
- CVE-2017-5753NVD 5.6EG 9.0EPSS p100CRITICAL
Frequently asked(4)
What is CVE-2026-28490?
When was CVE-2026-28490 disclosed?
What is the CVSS score of CVE-2026-28490?
How do I remediate CVE-2026-28490?
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-28490
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