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CVE-2026-58214

NATS Server: MQTT subscribe ACL bypass via $MQTT.deliver.pubrel prefix (incomplete fix for CVE-2026-33217)

Published: Jul 8, 2026Updated: Jul 13, 2026 Sources: CVE List NVDCWE-863
4.3MEDIUM
NVD MITRE
EPSS Score
0.3%
Top 82.9%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
Not available

Description

NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.3 and 2.12.12, an authenticated MQTT client could subscribe to the internal $MQTT.deliver.pubrel subject family, bypassing configured subscribe permissions and exposing MQTT QoS2 protocol metadata for sessions in the account. This issue is fixed in versions 2.14.3 and 2.12.12.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:LUI:NS:UC:LI:NA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:LConfidentiality
Low
I:NIntegrity
None
A:NAvailability
None
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Weaknesses

CWE-863

Affected Products

nats-io
oss-project
nats-serverOn-prem
Databases / cache-message-queue
linuxfoundation
oss-project·USaka yocto, pytorch, everest
nats-serverOn-premDatabase
AI / ML / vector-db-rag

Exploitability

Official Patch Available

Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques
Initial Access
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References

https://github.com/nats-io/nats-server/security/advisories/GHSA-4g68-3pwx-5vfj
github.com
https://github.com/nats-io/nats-server/commit/297b166be60fe13144084eed4b25201ead03204a
github.com
https://github.com/nats-io/nats-server/commit/34b09657bb596d5f850eaa5cfc97ea6b2f989a97
github.com
and 2 more references View all →

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