5.9

CVE-2026-84185: Jwcrypto: jwcrypto: general json jws kid binding bypass during jwkset verification

Awaiting analysis
AliasesUBUNTU-CVE-2026-84185DEBIAN-CVE-2026-84185
Published 03-09-2026Last modified 04-09-2026

Vulnerability summary

CVE-2026-84185 is a medium (CVSS 5.9) vulnerability in python-jwcrypto. EPSS estimates a 0.13% chance of exploitation in the next 30 days, higher than 2.7% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.9, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.9/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.13%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 4 · Related 4
OPENSUSE-SU-2026:11712-1OPENSUSE-SU-2026:21827-1SUSE-SU-2026:23702-1SUSE-SU-2026:23722-1

Timeline

  1. 03-09-2026
    PublishedVulnerability first disclosed.
  2. 04-09-2026
    Last modifiedVulnerability information updated.

Description

A flaw was found in the jwcrypto library, which is used for implementing Javascript Object Signing and Encryption (JOSE) standards. The issue occurs when the library verifies a General JSON Serialization JWS using a set of keys. Due to a coding error, the library fails to correctly identify the specific key ID (kid) and may instead accept a signature made by any valid key in the set. This can allow an attacker with a valid key to bypass authorization checks in applications that rely on the key ID to identify specific tenants or users.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.13%

Chance of exploitation in the next 30 days

Percentile

3%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.13% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Debian1 product
  • python-jwcryptoAll versions (No fix recorded)
Ubuntu1 product
  • python-jwcryptoAll versions (No fix recorded)

2 vendors · 2 products

References

5 links