CVE-2026-58214

EUVD-2026-42387
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
4.3 MEDIUM
NETWORK
LOW
LOW
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: 17.47%
Affected Products (NVD)
VendorProductVersion
linuxfoundationnats-server
𝑥
< 2.12.12
linuxfoundationnats-server
2.14.0 ≤
𝑥
< 2.14.3
𝑥
= Vulnerable software versions
Debian logo
Debian Releases
Debian Product
Codename
nats-server
bookworm
vulnerable
forky
2.14.3-1
fixed
sid
2.14.3-1
fixed
trixie
vulnerable
Ubuntu logo
Ubuntu Releases
Ubuntu Product
Codename
nats-server
jammy
dne
noble
needs-triage
questing
ignored
resolute
needs-triage
Common Weakness Enumeration
References
https://github.com/nats-io/nats-server/commit/297b166be60fe13144084eed4b25201ead03204a
https://github.com/nats-io/nats-server/commit/34b09657bb596d5f850eaa5cfc97ea6b2f989a97
https://github.com/nats-io/nats-server/releases/tag/v2.12.12
https://github.com/nats-io/nats-server/releases/tag/v2.14.3
https://github.com/nats-io/nats-server/security/advisories/GHSA-4g68-3pwx-5vfj