VulnerabilityAnalyzed

CVE-2026-66273

A pre-authentication attacker could leverage type size/count handling to cause excessive allocation leading to potential denial of service.

HIGH 7.5EPSS 0.43%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.43%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

A pre-authentication attacker could leverage type size/count handling to cause excessive allocation leading to potential denial of service. This issue affects Apache Qpid Proton-J: through 0.34.1. Users are recommended to upgrade to version 0.35.0, which fixes the issue.

CVSS 3.1: 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS: 0.43% probability · 36th percentile
CISA KEV: Not listed
Weakness: CWE-789
Affected: apache/qpid proton-j
Source: security@apache.org

References

https://lists.apache.org/thread/z34s9v5w05qk4qqtz5fs3v9wpxz6fnbhMailing List, Vendor Advisory
http://www.openwall.com/lists/oss-security/2026/08/04/9Mailing List, Third Party Advisory

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.