How severe is CVE-2026-33215?

CVE-2026-33215 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability low.

Is CVE-2026-33215 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-33215?

CVE-2026-33215 affects Linuxfoundation Nats-server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-33215?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-33215 have an EU (EUVD) identifier?

Yes. CVE-2026-33215 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-15017.

When was CVE-2026-33215 published?

CVE-2026-33215 was published on 2026-03-24 and last updated on 2026-06-17.

CVE-2026-33215

CVE-2026-33215 is a medium-severity vulnerability in Linuxfoundation Nats-server with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-287.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 0% (15th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-15017
Weakness: CWE-287
Affected product: Linuxfoundation Nats-server
Published: 2026-03-24
Last modified: 2026-06-17

Description

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The nats-server provides an MQTT client interface. Prior to versions 2.11.15 and 2.12.5, Sessions and Messages can by hijacked via MQTT Client ID malfeasance. Versions 2.11.15 and 2.12.5 patch the issue. No known workarounds are available.

Frequently asked questions

What is CVE-2026-33215?: NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The nats-server provides an MQTT client interface. Prior to versions 2.11.15 and 2.12.5, Sessions and Messages can by hijacked via MQTT Client ID malfeasance. Versions 2.11.15 and 2.12.5 patch the issue. No known workarounds are available.
How severe is CVE-2026-33215?: CVE-2026-33215 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability low.
Is CVE-2026-33215 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-33215?: CVE-2026-33215 affects Linuxfoundation Nats-server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-33215?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-33215 have an EU (EUVD) identifier?: Yes. CVE-2026-33215 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-15017.
When was CVE-2026-33215 published?: CVE-2026-33215 was published on 2026-03-24 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*

More vulnerabilities in Linuxfoundation Nats-server

CVE-2022-28357 — Critical (CVSS 9.8): NATS nats-server 2.2.0 through 2.7.4 allows directory traversal because of an unintended path to a management action…
CVE-2020-26892 — Critical (CVSS 9.8): The JWT library in NATS nats-server before 2.1.9 has Incorrect Access Control because of how expired credentials are…
CVE-2022-24450 — High (CVSS 8.8): NATS nats-server before 2.7.2 has Incorrect Access Control. Any authenticated user can obtain the privileges of the…
CVE-2026-33216 — High (CVSS 8.6): NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions…
CVE-2026-33218 — High (CVSS 7.5): NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions…
CVE-2026-29785 — High (CVSS 7.5): NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions…

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Other CWE-287 (Improper Authentication) vulnerabilities

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CVE-2026-42822 — Critical (CVSS 10.0): Improper authentication in Azure Local Disconnected Operations allows an unauthorized attacker to elevate privileges…
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