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CVE-2026-102271

Pyjwt vulnerability

7.4 HIGHPublic exploitEPSS 0.18%
  1. Published28 Sept 2026

Description

PyJWT is a Python implementation of JSON Web Token standards. From 2.4.0 until 2.14.0, PyJWT HMACAlgorithm.prepare_key is affected because asymmetric-key guard relies on textual markers that are absent from DER encoding. This occurs when an application mixes HMAC and asymmetric algorithms and supplies a DER public key as the shared verification key. As a result, PyJWT uses public DER bytes as an HMAC secret. Consequently, an attacker who knows the public key can forge authenticated HMAC tokens. This issue is fixed in version 2.14.0.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityHigh
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityNone
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

Pyjwt≥ 2.4.0 < 2.14.0

Remediation

Fixed in
Pyjwt≥ 2.14.0

References

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Frequently asked

Is CVE-2026-102271 being actively exploited?

CVE-2026-102271 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.18%.

How severe is CVE-2026-102271?

CVE-2026-102271 has a CVSS 3.1 base score of 7.4, rated high. EPSS estimates a 0.18% probability of exploitation.

Which products are affected by CVE-2026-102271?

Affected products include Pyjwt.

How do I fix CVE-2026-102271?

Upgrade affected software to a fixed version, for example Pyjwt 2.14.0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-102271 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.