joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to 1.6.8, joserfc.jwt.decode accepts attacker-forged HMAC-signed tokens when the caller-supplied verification key is the empty string or None, because HMACAlgorithm.sign and HMACAlgorithm.verify in src/joserfc/_rfc7518/jws_algs.py pass the output of OctKey.get_op_key(...) to hmac.new(...) and OctKey.import_key in src/joserfc/_rfc7518/oct_key.py only emits a SecurityWarning for keys shorter than 14 bytes without rejecting zero-length input. This issue is fixed in version 1.6.8.

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

  - joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption
    (JOSE) standards. Prior to 1.6.8, joserfc.jwt.decode accepts attacker-forged HMAC-signed tokens when the
    caller-supplied verification key is the empty string or None, because HMACAlgorithm.sign and
    HMACAlgorithm.verify in src/joserfc/_rfc7518/jws_algs.py pass the output of OctKey.get_op_key(...) to
    hmac.new(...) and OctKey.import_key in src/joserfc/_rfc7518/oct_key.py only emits a SecurityWarning for
    keys shorter than 14 bytes without rejecting zero-length input. This issue is fixed in version 1.6.8.
    (CVE-2026-49852)

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

  - joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption     (JOSE) standards. Prior to 1.6.8, joserfc.jwt.decode accepts attacker-forged HMAC-signed tokens when the     caller-supplied verification key is the empty string or None, because HMACAlgorithm.sign and     HMACAlgorithm.verify in src/joserfc/_rfc7518/jws_algs.py pass the output of OctKey.get_op_key(...) to     hmac.new(...) and OctKey.import_key in src/joserfc/_rfc7518/oct_key.py only emits a SecurityWarning for     keys shorter than 14 bytes without rejecting zero-length input. This issue is fixed in version 1.6.8.
    (CVE-2026-49852)

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

The remote openSUSE 16 host has a package installed that is affected by a vulnerability as referenced in the openSUSE- SU-2026:21263-1 advisory.

    Changes in python-joserfc:

    - CVE-2026-49852: HS256/HS384/HS512 verify accepts empty/nil HMAC key (bsc#1270234)

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

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

ID	Name	Product	Family	Type	Severity
457284	Echo: joserfc: security update to 1.6.8	Tenable Cloud Security	Echo Local Security Checks	Local	high
457284	Echo: joserfc: security update to 1.6.8	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	high
327782	Linux Distros Unpatched Vulnerability : CVE-2026-49852	Nessus	Misc.	Local	high
326067	openSUSE 16 Security Update : python-joserfc (openSUSE-SU-2026:21263-1)	Nessus	SuSE Local Security Checks	Local	high

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CVE-2026-49852

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Tenable Plugins

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high

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