CVE-2026-58214
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.
Does this matter?
Lower severity and a low EPSS score (0.35%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 3.1
- 4.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
- EPSS
- 0.35% probability · 28th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-863
- Affected
- linuxfoundation/nats-server
- Source
- security-advisories@github.com
References
- https://github.com/nats-io/nats-server/commit/297b166be60fe13144084eed4b25201ead03204aPatch
- https://github.com/nats-io/nats-server/commit/34b09657bb596d5f850eaa5cfc97ea6b2f989a97Patch
- https://github.com/nats-io/nats-server/releases/tag/v2.12.12Release Notes
- https://github.com/nats-io/nats-server/releases/tag/v2.14.3Release Notes
- https://github.com/nats-io/nats-server/security/advisories/GHSA-4g68-3pwx-5vfjVendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.