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🛡️ CVE-2026-66273 — qpid-proton-j

🟠 CVSS 7.5 — High ✅ No Known Exploit CWE-789 NVD
7.5
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: None.
  • Integrity impact: None.
  • Availability impact: High — total loss, or loss the attacker controls.

Weakness class

CVE-2026-66273 is classified as CWE-789: Memory Allocation with Excessive Size Value. The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.

Affected software

CVE-2026-66273 is recorded against 1 package.

  • qpid-proton-j (fixed in 0.35.0)

Timeline and source

Published on 5 August 2026 and last revised on 7 August 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

lists.apache.org
www.openwall.com

Other advisories for this package

qpid-proton-j has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-789: Memory Allocation with Excessive Size Value) in other software:

Details

Severity HIGH
CVSS Score 7.5
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE CWE-789
Public Exploit ✅ No
Source NVD
Published 2026-08-05
Updated 2026-08-20
Modified 2026-08-07
Fix URL N/A

Affected Packages

Software From version Fixed in
qpid-proton-j — 0.35.0

Similar Threats

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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