Is CVE-2026-33223 in the CISA KEV catalog?

No. CVE-2026-33223 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-33223?

CVE-2026-33223 has a CVSS v3 base score of 6.4 (MEDIUM).

What is the EPSS score for CVE-2026-33223?

CVE-2026-33223 has an EPSS score of 0.21% (11th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-33223?

Upgrade nats-server on debian unstable to 2.12.6-1 or later.

CVE & CISA-KEV Catalog

CVE-2026-33223

MEDIUM

6.4

CVSS v3

NVD

Description

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, the NATS message header `Nats-Request-Info:` is supposed to be a guarantee of identity by the NATS server, but the stripping of this header from inbound messages was not fully effective. An attacker with valid credentials for any regular client interface could thus spoof their identity to services which rely upon this header. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.

CWE-290

How to fix

Remediation Available

nats-serverDebian

Fixed in:2.12.6-1CVE-2026-33223

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeChanged

Impact

ConfidentialityLow

IntegrityLow

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

Exploit Intelligence

0.21%probability of exploitation in 30 days

11thpercentile

Low risk: more likely to be exploited than 11% of all known CVEs.

References

Vendor Advisory2

Related Vulnerabilities

Other CWE-290 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-4358	Critical	9.8	97%	KEV	-
CVE-2022-24112	Critical	9.8	96%	KEV	Fix
CVE-2022-23131	Critical	9.1	96%	KEV	-
CVE-2021-29441	High	8.6	74%	-	Fix
CVE-2021-31195	Medium	6.5	74%	-	Fix
CVE-2020-7388	Critical	10.0	70%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-03-26.