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.

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-3298 advisory.

    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. (CVE-2026-101917)

    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-2026-101918)

    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-2026-102266)

    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-2026-102267)

    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-2026-102268)

    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-2026-102271)

    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-2026-102272)

    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-2026-102273)

    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-2026-102275)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of Tencent Linux installed on the remote TencentOS Server 4 host is prior to tested version. It is, therefore, affected by multiple vulnerabilities as referenced in the TSSA-2026:1087 advisory.

    Package updates are available for TencentOS Server 4 that fix the following vulnerabilities:

    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-2026-102268:
    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-2026-102266:
    PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0,     HMACAlgorithm.from_jwk is affected because PyJWK verification path used the decoded key without applying     prepare_key validation. This occurs when a trusted JWK Set contains an oct entry with an empty k value. As     a result, an attacker signs an HMAC token with the same zero-length key accepted by PyJWT. Consequently,     forged token can carry arbitrary authenticated claims. This issue is fixed in version 2.14.0.

Tenable has extracted the preceding description block directly from the Tencent Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - 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-2026-102268)

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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-2026-102268)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
371882	Amazon Linux 2023 : python3-jwt, python3-jwt+crypto (ALAS2023-2026-3298)	Nessus	Amazon Linux Local Security Checks	Local	critical
365155	TencentOS Server 4: python-jwt (TSSA-2026:1087)	Nessus	Tencent Local Security Checks	Local	critical
462086	Echo: pyjwt: security update to 2.14.0	Tenable Cloud Security	Echo Local Security Checks	Local	critical
462086	Echo: pyjwt: security update to 2.14.0	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	critical
351353	Linux Distros Unpatched Vulnerability : CVE-2026-102268	Nessus	Misc.	Local	critical

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