Apache Qpid ProtonJ2: Incoming session flow control window can be exceeded (CVE-2026-67591) | HOL Guard CVE

Medium · CVSS 6.5CVE-2026-67591

Apache Qpid ProtonJ2: Incoming session flow control window can be exceeded

Answer in brief

CVE-2026-67591 records a Medium severity (CVSS 6.5) vulnerability in Apache Qpid ProtonJ2: Incoming session flow control window can be exceeded. The current sources do not mark it as known exploited. The current feed maps Apache Software Foundation/Apache Qpid ProtonJ2 (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 5, 2026Updated Aug 7, 2026Source checked Sep 19, 2026First seen by HOL Aug 5, 2026Material review Aug 7, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 6.5
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Not reported

Why this deserves its current priority

CVSS is 6.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Apache Software Foundation/Apache Qpid ProtonJ2 (generic). Check affected ranges and fixed versions before updating.

Affected products and reported versions
Product	Affected versions	Fixed versions
cpe:2.3:a:apache:qpid_protonj2::::::::	Not reported	Not reported

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Apache Software Foundation/Apache Qpid ProtonJ2generic	0	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Apache Software Foundation/Apache Qpid ProtonJ2.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 7, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 5, 2026

Sources and claim methodology

Upstream source description

An authenticated attacker could exceed the session flow control incoming window potentially leading to denial of service. This issue affects Apache Qpid ProtonJ2: through 1.1.0. Users are recommended to upgrade to version 1.2.0, which fixes the issue.

Quoted source text, attributed separately from HOL analysis.