PatchTheCVECVE-2026-66257: A pre-authentication attacker could leverage unbounded symbol value caching to cause resource exhaustion leadi
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HIGH 7.5REMOTEWATCHLISTUPGRADE
CVE-2026-66257 is a high-severity flaw (CVSS 7.5) affecting qpid proton-j. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
A pre-authentication attacker could leverage unbounded symbol value caching to cause resource exhaustion leading to 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.
Why this priority
- High severity
- Remotely exploitable, no login, no user action
- On your watchlist
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.5 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.8% (top 45%) |
| CISA exploited list | No |
| Weakness | CWE-770 |
| Published | 2026-08-05 |
| Last modified | 2026-10-23 |
Publisher (CNA): Apache Software Foundation · Vendor: apache
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
apache qpid proton-j UPGRADE
Affected: < 0.35.0
Fixed in: 0.35.0
Safe to downgrade to: no unaffected older release
1. Check installed version
apt-cache policy qpid-proton-j || rpm -q qpid-proton-j || qpid-proton-j --version
2. UPGRADE to 0.35.0 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade qpid-proton-j
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade qpid-proton-j
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
Exact fixes by distribution
Fedora 46 · python-streamlink · FIXED · 8.6.2-1.fc46 · FEDORA-2026-a56fcfdc08 · source
sudo dnf upgrade --advisory=FEDORA-2026-a56fcfdc08
Fedora ELN · valgrind · FIXED · 3.28.0-1.eln159 · FEDORA-2026-c593ef1d15 · source
sudo dnf upgrade --advisory=FEDORA-2026-c593ef1d15
Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Related CVEs
- CVE-2026-66273 HIGH 7.5 UPGRADE A pre-authentication attacker could leverage type size/count handling to cause excessive allocation leading to
- CVE-2026-66274 HIGH 7.5 UPGRADE A pre-authentication attacker could leverage type nesting to cause a StackOverflowError potentially leading to
- CVE-2026-66275 MEDIUM 6.5 UPGRADE An authenticated attacker could exceed the session flow control incoming window potentially leading to denial
- CVE-2026-66276 MEDIUM 6.5 UPGRADE An authenticated attacker can craft a disposition frame with large or illegal ranges causing excessive CPU usa
- CVE-2026-66277 MEDIUM 6.5 UPGRADE It was not possible to govern the maximum number of transfer frames per incoming delivery, enabling an authent