CVE-2026-28802: authlib
Vulnerability summary
CVE-2026-28802 is a critical (CVSS 9.8) vulnerability in authlib. EPSS estimates a 0.57% chance of exploitation in the next 30 days, higher than 46% of scored vulnerabilities. 1 public exploit is recorded.
Advisory lineage
Upstream 0 · Downstream 0 · Related 1Timeline
- 06-03-2026PublishedVulnerability first disclosed.
- 10-09-2026Last modifiedVulnerability information updated.
Description
Authlib is a Python library which builds OAuth and OpenID Connect servers. From version 1.6.5 to before version 1.6.7, previous tests involving passing a malicious JWT containing alg: none and an empty signature was passing the signature verification step without any changes to the application code when a failure was expected.. This issue has been patched in version 1.6.7.
CVSS metrics
10 scores · 7 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:PDiffers
- OSV · WolfiEcosystem advisory · calculated8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:PDiffers
- OSV · ChainguardEcosystem advisory · calculated8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:PDiffers
- NVDNIST7.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- CVE.orgCNA9.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:NDiffers
- OSV · PypiEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · UbuntuEcosystem advisory · calculated9.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:NDiffers
- OSV · DebianEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.57%
Chance of exploitation in the next 30 days
Percentile
46%
Versus all other CVEs
30-day change
+0.14 pp
From 0.43% on 20-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundAuthlib
Maturity: poc
Weaknesses
CWE · root causeAffected systems
Authlib1 product
- authlib≥ 1.6.5, < 1.6.7
Chainguard1 product
- airflow-3< 3.1.8-r0
Debian1 product
- python-authlibAll versions (No fix recorded) | < 1.6.7-1
PyPI1 product
- authlib≥ 1.6.5, < 1.6.7
Ubuntu1 product
- python-authlibAll versions (No fix recorded)
Wolfi1 product
- airflow-3< 3.1.8-r0
6 vendors · 6 products
References
18 links- github.com/authlib/authlib/security/advisories/GHSA-7wc2-qxgw-g8ggX Refsource CONFIRMWEBEVIDENCEREPORTAdvisoryExploitVendor Advisory
- github.com/authlib/authlib/commit/a61c2acb807496e67f32051b5f1b1d5ccf8f0a75X Refsource MISCWEBFIXREPORTPatch
- github.com/authlib/authlib/commit/b87c32ed07b8ae7f805873e1c9cafd1016761df7X Refsource MISCWEBFIXREPORTPatch
Show all 18 references
- github.com/authlib/authlibPACKAGE
