9.8

CVE-2026-66909: apache software foundation apache cxf Deserialization of Untrusted Data

CVSS: 9.8v3.1CriticalModified
Published 06-08-2026Last modified 07-08-2026
Open JSON

Vulnerability summary

CVE-2026-66909 is a critical (CVSS 9.8) Deserialization of Untrusted Data vulnerability in apache software foundation apache cxf. EPSS estimates a 1.15% chance of exploitation in the next 30 days, higher than 66.3% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.8/10
010
Critical · v3.1 (CVE.org)
EPSS score
1.15%
0%100%
Low · +0.48 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 06-08-2026
    PublishedVulnerability first disclosed.
  2. 07-08-2026
    Last modifiedVulnerability information updated.

Description

Apache CXF's JMS transport deserializes the body of any inbound JMS ObjectMessage using native Java deserialization, with no type restrictions in place. Any attacker able to place a message on the service's JMS destination can submit a malicious serialized object, leading to denial of service or, if a suitable gadget class is on the classpath, remote code execution. The fix disables ObjectMessage deserialization by default, with a configuration switch to re-enable it if needed. Users are recommended to upgrade to versions 4.2.3 or 4.1.8 or 3.6.12, which fix this issue.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

1.15%

Chance of exploitation in the next 30 days

Percentile

66%

Versus all other CVEs

30-day change

+0.48 pp

From 0.67% on 18-09-2026

18-09-202618-10-2026
EPSS score
1.15%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Apache1 product
  • cxf< 3.6.12 | ≥ 4.0.0, < 4.1.8 | ≥ 4.2.0, < 4.2.3
Apache software foundation1 product
  • apache cxf≥ 4.2.0, < 4.2.3 | ≥ 4.0.0, < 4.1.8 | < 3.6.12

2 vendors · 2 products

References

2 links