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High ALAS2023-2026-3298 9 CVEs

Important: python-jwt security update (Amazon Linux 2023)

Published Oct 26, 2026 · Updated Oct 26, 2026

Summary

Package updates are available for Amazon Linux 2023 that fix the following vulnerabilities: CVE-2026-102275: PyJWT is a Python implementation of JSON Web Token standards. From 2.1.0 until 2.15.0, PyJWT OKPAlgorithm.from_jwk in jwt/algorithms.py is affected because private-JWK import path does not compare the public key derived from d with x. This occurs when an OKP private JWK supplies non-corresponding x and d components. As a result, identity derived from x can differ from operations performed with d. Consequently, if an integration also accepts private key parameters from a proof header without rejecting them, an attacker may use a stolen sender-constrained token without the legitimate private key. This issue is fixed in version 2.15.0. CVE-2026-102273: PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, PyJWT HMACAlgorithm.prepare_key is affected because HMAC key guard only recognizes top-level public JWK forms and misses container representations. This occurs when an application allows HMAC and asymmetric algorithms and passes a public JWK container as the raw key. As a result, public asymmetric key material is accepted as the HMAC secret. Consequently, an attacker who knows the public key can forge a token with arbitrary authenticated claims. This issue is fixed in version 2.14.0. CVE-2026-102272: PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, HMACAlgorithm.prepare_key in jwt/algorithms.py is affected because raw-JWK detector does not normalize accepted Unicode byte-order marks before checking for JSON. This occurs when a public JWK is prefixed with a UTF-8 BOM and used in a mixed-algorithm verification path. As a result, public JWK bypasses asymmetric-key detection and becomes the HMAC secret. Consequently, an attacker who knows the public key can forge authenticated tokens. This issue is fixed in version 2.14.0. CVE-2026-102271: 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. CVE-2026-102268: PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, is_pem_format in jwt/utils.py is affected because is_pem_format does not recognize every PEM representation accepted by the cryptography loader. This occurs when an application mixes HMAC and asymmetric algorithms and supplies a mutated public-key PEM as raw key bytes. As a result, HMACAlgorithm.prepare_key treats the unrecognized asymmetric public key 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. CVE-2026-102267: PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, PyJWT PyJWKClient is affected because redirect destinations are not revalidated against the JWKS trust boundary. This occurs when a configured trusted JWKS endpoint returns an attacker-influenced redirect. As a result, PyJWKClient follows the redirect and consumes the redirected response as key material. Consequently, forwarded credentials may be disclosed or verification keys may be substituted. This issue is fixed in version 2.14.0. CVE-2026-102266: A flaw was found in pyjwt. A remote attacker can forge authentication tokens and bypass security controls by signing tokens with an empty key. When verifying tokens against a JSON Web Key (JWK) set that contains an empty Hash-based Message Authentication Code (HMAC) key, the library fails to enforce key-length validation. This allows an attacker to generate valid tokens carrying arbitrary claims to gain unauthorized access. CVE-2026-101918: A flaw was found in PyJWT. When processing a JSON Web Token (JWT) prior to signature verification, the parser fails to properly handle deeply nested data, leading to an unhandled recursion error. A remote unauthenticated attacker could exploit this flaw by submitting a specially crafted token, causing the application to raise an unexpected server exception and resulting in a Denial of Service (DoS). CVE-2026-101917: A flaw was found in PyJWT. A remote attacker can trigger a Denial of Service (DoS) through outbound request amplification by submitting tokens containing unknown key identifiers. Because the library does not cache lookup failures or enforce a minimum refresh interval when fetching signing keys, each invalid key identifier forces a new request to the remote JSON Web Key Set (JWKS) server. This allows an attacker to exhaust network resources and overwhelm the configured authentication endpoints.

Fixed packages 2

ReleasePackageFixed in
Amazon Linux · 2023 python3-jwt 0:2.4.0-1.amzn2023.0.6
Amazon Linux · 2023 python3-jwt+crypto 0:2.4.0-1.amzn2023.0.6

Vulnerabilities 9

References

  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-101917.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-101918.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-102266.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-102267.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-102268.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-102271.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-102272.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-102273.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-102275.html