Trending
CVE-2026-28498

CVE detail

CVE-2026-28498

Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.9, a library-level vulnerability was identified in the Authlib Python library concerning the validation of OpenID Connect (OIDC) ID Tokens. Specifically, the internal hash verification logic (_verify_hash) responsible for validating the at_hash (Access Token Hash) and c_hash (Authorization Code Hash) claims exhibits a fail-open behavior when encountering an unsupported or unknown cryptographic algorithm. This flaw allows an attacker to bypass mandatory integrity protections by supplying a forged ID Token with a deliberately unrecognized alg header parameter. The library intercepts the unsupported state and silently returns True (validation passed), inherently violating fundamental cryptographic design principles and direct OIDC specifications. This issue has been patched in version 1.6.9.

CVSS 8.2 · HighBuzz score 38.6

Buzz score

Why this CVE is surfacing

Buzz score total 38.6

This all-time snapshot uses the same composite formula as Trending across a 30-year evidence window, rather than a current rolling window.

Buzz score components · mention 25.6 · diversity 13.0 · KEV 0.0 · OTX 0.0 · PoC 0.0

Mention score

25.6

12 evidence mentions in the snapshot

Diversity score

13.0

4 sources across 2 categories

KEV score

0.0

No KEV entry observed

OTX score

0.0

0 OTX pulses

PoC score

0.0

0 repos · best confidence N/A

Best PoC traction

Maximum stars on a matched PoC repo

Why it matters now

Mention timeline

Total mentions: 0; within the 30d window
Peak daily: 0; highest bucket

Evidence

Source links by recency

Newest mentions first

12 source links · newest first

https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-28498.jsonsecurity.access.redhat.com
No excerpt available.
Vendor Advisorysecurity.access.redhat.comMar 16, 2026, 6:16 PM
https://bugzilla.redhat.com/show_bug.cgi?id=2448182bugzilla.redhat.com
No excerpt available.
Exploitbugzilla.redhat.comMar 16, 2026, 6:16 PM
https://access.redhat.com/security/cve/CVE-2026-28498access.redhat.com
No excerpt available.
Vendor Advisoryaccess.redhat.comMar 16, 2026, 6:16 PM
https://access.redhat.com/errata/RHSA-2026:6912access.redhat.com
No excerpt available.
Vendor Advisoryaccess.redhat.comMar 16, 2026, 6:16 PM
https://access.redhat.com/errata/RHSA-2026:6720access.redhat.com
No excerpt available.
Vendor Advisoryaccess.redhat.comMar 16, 2026, 6:16 PM
https://access.redhat.com/errata/RHSA-2026:6568access.redhat.com
No excerpt available.
Vendor Advisoryaccess.redhat.comMar 16, 2026, 6:16 PM
https://access.redhat.com/errata/RHSA-2026:6567access.redhat.com
No excerpt available.
Vendor Advisoryaccess.redhat.comMar 16, 2026, 6:16 PM
https://access.redhat.com/errata/RHSA-2026:6497access.redhat.com
No excerpt available.
Vendor Advisoryaccess.redhat.comMar 16, 2026, 6:16 PM
https://access.redhat.com/errata/RHSA-2026:6309access.redhat.com
No excerpt available.
Vendor Advisoryaccess.redhat.comMar 16, 2026, 6:16 PM
https://github.com/authlib/authlib/security/advisories/GHSA-m344-f55w-2m6jgithub.com
No excerpt available.
Exploitgithub.comMar 16, 2026, 6:16 PM
https://github.com/authlib/authlib/releases/tag/v1.6.9github.com
No excerpt available.
Exploitgithub.comMar 16, 2026, 6:16 PM
https://github.com/authlib/authlib/commit/b9bb2b25bf8b7e01512d847a95c1749646eaa72bgithub.com
No excerpt available.
Exploitgithub.comMar 16, 2026, 6:16 PM

Exploit code

Public exploit repository references

Public PoC repositories are third-party, potentially unsafe artifacts. Treat their code as untrusted and use it only on authorized systems in an isolated, least-privilege environment. cvebuzz does not execute the code or verify that an exploit works.

0 repository references · best confidence N/A · max 0 stars

No public PoC repositories have been matched yet.

Related records

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External lookup

Potential internet exposure

Potential exposure only — not proof of vulnerability.Shodan results indicate potentially internet-exposed products, not confirmed vulnerable systems. They do not confirm that any returned system is vulnerable to CVE-2026-28498.

Product-level CPE searches intentionally omit version fields and NVD version-range or configuration certainty. Verify the exact product version and configuration independently.

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Product CPE queries

Derived from this CVE's existing NVD CPE 2.3 records; the application, operating-system, or hardware part is retained.

cpe:2.3:a:authlib:authlibSearch this product on Shodan

Exact CVE query

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Shodan's exact vuln: filter is separate from the product searches above and requires an eligible paid Shodan plan.

vuln:CVE-2026-28498Search this CVE on Shodan

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Metadata

Canonical fields

NVD status

Modified

Published

Mar 16, 2026

Modified

Jul 20, 2026

Official record

Authoritative NVD record

CVSS vector

CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/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

CWE IDs

Vendor classifications

How this vector reads

CVSS 4.0 base metrics decoded below. This explanation does not recalculate or change the NVD score.

Attack Vector (AV): Network. The vulnerable system can be reached across network boundaries.
Attack Complexity (AC): High. Successful exploitation depends on conditions outside the attacker's control.
Attack Requirements (AT): Present. A prerequisite deployment or execution condition must be present.
Privileges Required (PR): None. The attacker needs no privileges on the vulnerable system.
User Interaction (UI): None. Exploitation does not require a targeted user to act.
Vulnerable System Confidentiality (VC): None. There is no direct impact to this security property.
Vulnerable System Integrity (VI): High. There is a total or serious impact to this security property.
Vulnerable System Availability (VA): None. There is no direct impact to this security property.
Subsequent System Confidentiality (SC): None. There is no direct impact to this security property.
Subsequent System Integrity (SI): None. There is no direct impact to this security property.
Subsequent System Availability (SA): None. There is no direct impact to this security property.

Optional CVSS v4 metrics remain in the raw vector; only base metrics are expanded here.

Signals

Exploitation indicators

0 stored signals · no KEV · 0 OTX pulses