CVE & CISA-KEV Catalog

CVE-2026-49852

HIGH
8.7
CVSS v4
NVD

Description

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.

CWE-287Improper AuthenticationCWE-326CWE-1391

How to fix

Remediation Available
joserfcDebian
Fixed in:1.6.8-1CVE-2026-49852

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Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v4 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone

Impact

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Exploit Intelligence

0.19%probability of exploitation in 30 days
9thpercentile

Low risk: more likely to be exploited than 9% of all known CVEs.

References

Related Vulnerabilities

Other CWE-287 (Improper Authentication) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2023-35082Critical9.8100%KEV + RansomFix
CVE-2023-35078Critical9.8100%KEV + RansomFix
CVE-2017-7921Critical9.8100%KEV-
CVE-2024-7593Critical9.8100%KEV-
CVE-2023-46805High8.2100%KEV + Ransom-
CVE-2022-40684Critical9.8100%KEV + RansomFix
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-07-20.