CVE-2026-58214
NATS Server: MQTT subscribe ACL bypass via $MQTT.deliver.pubrel prefix (incomplete fix for CVE-2026-33217)
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
NATS Server: MQTT subscribe ACL bypass via $MQTT.deliver.pubrel prefix (incomplete fix for CVE-2026-33217)
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.
- Record
CVE-2026-58214- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-863
- Updated
- 2026-11-02
EUVDEUVD-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.
- Record
EUVD-2026-42387- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-58214- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-863
- Updated
- 2026-11-02
OSV
NATS Server: MQTT subscribe ACL bypass via $MQTT.deliver.pubrel prefix (incomplete fix for CVE-2026-33217)
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.
- Record
CVE-2026-58214- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-863
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-58214
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.
- Record
DEBIAN-CVE-2026-58214- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Updated
- 2026-11-02
OSVJLSEC-2026-1149
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.
- Record
JLSEC-2026-1149- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Updated
- 2026-11-02
Show 4 moreShow less
OSVRHSA-2026:36016
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
- Record
RHSA-2026:36016- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVRHSA-2026:36017
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
- Record
RHSA-2026:36017- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-58214
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.
- Record
UBUNTU-CVE-2026-58214- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Updated
- 2026-11-02
OSVBIT-nats-2026-58214 No score
NATS Server: MQTT subscribe ACL bypass via $MQTT.deliver.pubrel prefix (incomplete fix for CVE-2026-33217)
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.
- Record
BIT-nats-2026-58214- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
natsBitnami |
before 2.12.12, 2.14.0 up to 2.14.3 | 2.12.122.14.3 |
nats-serverDebian:12 |
All versions, plus listed versions 2.10.1-12.10.16-12.10.18-12.10.24-12.10.27-1 Show 11 moreShow less2.10.3-12.10.4-12.10.7-12.12.4-12.12.6-12.14.1-12.14.3-12.14.6-12.15.1-12.9.10-12.9.19-1 |
None known |
nats-serverDebian:13 |
All versions, plus listed versions 2.10.27-12.12.4-12.12.6-12.14.1-12.14.3-12.14.6-12.15.1-1 |
None known |
nats-serverDebian:14 |
before 2.14.3-1, plus listed versions 2.10.27-12.12.4-12.12.6-12.14.1-1 |
2.14.3-1 |
nats_server_jllJulia |
before 2.14.3+0 | 2.14.3+0 |
nats-server2.14Red Hat:hummingbird:1 From an advisory covering 6 CVEs |
before 0:2.14.3-1.hum1 | 0:2.14.3-1.hum1 |
nats-server2.12Red Hat:hummingbird:1 From an advisory covering 6 CVEs |
before 0:2.12.12-1.hum1 | 0:2.12.12-1.hum1 |
nats-serverUbuntu:24.04:LTS |
All versions, plus listed versions 2.9.19-1build12.10.3-12.10.4-12.10.7-12.10.7-1ubuntu0.12.10.7-1ubuntu0.22.10.7-1ubuntu0.3 |
None known |
nats-serverUbuntu:25.10 |
All versions, plus listed versions 2.10.24-12.10.27-1 |
None known |
nats-serverUbuntu:26.10 |
All versions, plus listed versions 2.10.27-1build12.14.1-12.14.3-1 |
None known |
nats-serverUbuntu:Pro:26.04:LTS |
All versions, plus listed versions 2.10.27-12.10.27-1build12.10.27-1ubuntu0.26.04.1~esm1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-58214 is a medium vulnerability (CVSS 4.3) in Linuxfoundation Nats-server, published July 8, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.35%, the 28th percentile. Fixed in nats 2.12.12.
References
github.com/nats-io/nats-server/security/advisories/GHSA-4g68-3pwx-5vfj
nvd.nist.gov/vuln/detail/CVE-2026-58214
Show 50 moreShow less
security-tracker.debian.org/tracker/CVE-2026-58214
access.redhat.com/errata/RHSA-2026:36016
images.redhat.com
security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_36016.json
bugzilla.redhat.com/show_bug.cgi?id=2498259
cve.org/CVERecord?id=CVE-2026-58209
ubuntu.com/security/CVE-2026-58214