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VulnerabilityPublished Updated

CVE-2026-33247: nats-server · Insertion of Sensitive Information Into Debugging Code

Affects nats-serverSource CVE Database V5

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Not known to be exploited · CVSS 7.4 High : upgrade to 2.12.6 or 2.11.15 soon.

Data as of 10 Nov 2026, 23:24 UTC

CVSS 3.1 base score
7.4High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.4% chance of exploitation in 30 days – higher than 37% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 2.12.6, 2.11.15
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 10 Nov 2026.

What to do

Upgrade nats-server to 2.12.6 or 2.11.15; nats-io/nats-server to 2.11.15.

Affected software

ProductAffectedFixed in
nats-ionats-serverAffected
  • >=2.12.0-RC.1 <2.12.6
Fixed in
  • 2.12.6
nats-ionats-serverAffected
  • <2.11.15
Fixed in
  • 2.11.15
GitHubnats-io/nats-serverpkg:github/nats-io/nats-serverOther threatsAffected
  • <2.11.15
Fixed in
  • 2.11.15

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available in nats-server versions 2.11.15 and 2.12.6; upgrading to these or later versions is recommended. As a workaround, do not pass static credentials via command-line arguments; instead, configure them in a configuration file. Additionally, do not enable the monitoring port if credentials are passed via argv. Ensure the monitoring port is not exposed to untrusted or public networks to prevent unauthorized access. Follow vendor guidance and apply official patches when possible.

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, if a nats-server is run with static credentials for all clients provided via argv (the command-line), then those credentials are visible to any user who can see the monitoring port, if that too is enabled. The `/debug/vars` end-point contains an unredacted copy of argv. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, configure credentials inside a configuration file instead of via argv, and do not enable the monitoring port if using secrets in argv. Best practice remains to not expose the monitoring port to the Internet, or to untrusted network sources.

References

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