Is there a public exploit for CVE-2026-48523?

No public exploit for CVE-2026-48523 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-48523?

CVE-2026-48523 scores CVSS 5.4 (v3.1), rated medium. EPSS puts the chance of exploitation in the next 30 days at 0.13%.

What does CVE-2026-48523 affect?

CVE-2026-48523 affects jpadilla pyjwt.

5.4 Medium

PyJWT is a JSON Web Token implementation in Python.

CVE-2026-48523

[!NOTE] Scored assuming a deployment where algorithm policy functions as an authentication/authorization boundary. In deployments where the algorithm policy enforces crypto agility only, the practical confidentiality impact is lower and the issue is closer to an integrity-of-policy-enforcement bug. PyJWT 2.9.0 through 2.12.1 allows a verifier-side algorithm allow-list bypass when jwt.decode() or jwt.decodecomplete() are called with a PyJWK key. The token header alg is checked against the caller-supplied algorithms allow-list, but signature verification is performed with the algorithm bound to the PyJWK object instead of the header algorithm. An attacker who controls a registered JWK/JWKS private key can sign with a disallowed algorithm, advertise an allowed algorithm in the JWT header, and still be accepted. The issue affects the documented PyJWKClient.getsigningkeyfromjwt(...) flow. Summary PyJWT's PyJWK verification path allows a verifier-side algorithm allow-list bypass. In affected versions, when a JWT is decoded with a PyJWK object, PyJWT verifies that the header alg string is present in the caller's algorithms=[...] list, but it does not actually use the header algorithm to…

Assessment

CVSS: 5.4 (v3.1)
Severity: Medium
EPSS: 0.13% chance of exploitation in the next 30 days
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 28 May 2026
Last updated: 25 October 2026
Affected: jpadilla · pyjwt · pyjwt
Weakness: CWE-347
Assigner: security-advisories@github.com

CVSS vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

At the source

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