CVE-2026-33247: linuxfoundation nats-server
Vulnerability summary
CVE-2026-33247 is a high (CVSS 7.4) vulnerability in linuxfoundation nats-server. EPSS estimates a 0.54% chance of exploitation in the next 30 days, higher than 44.2% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 2 · Related 3Timeline
- 25-03-2026PublishedVulnerability first disclosed.
- 09-09-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
7 scores · 7 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated5.3MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:NDiffers
- OSV · DebianEcosystem advisory · calculated5.3MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:NDiffers
- OSV · WolfiEcosystem advisory · calculated7.4HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
- OSV · GoEcosystem advisory · calculated7.4HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
- OSV · ChainguardEcosystem advisory · calculated7.4HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
- NVDNIST5.3MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:NDiffers
EPSS trend
Probability
0.54%
Chance of exploitation in the next 30 days
Percentile
44%
Versus all other CVEs
30-day change
+0.12 pp
From 0.41% on 20-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-215Insertion of Sensitive Information Into Debugging CodeThe product inserts sensitive information into debugging code, which could expose this information if the debugging code is not disabled in production.
- CWE-214Invocation of Process Using Visible Sensitive InformationA process is invoked with sensitive command-line arguments, environment variables, or other elements that can be seen by other processes on the operating system.
Affected systems
Chainguard28 products
- k3s< 1.35.2.1-r4
- k3s-1.32< 1.32.13.1-r7
- k3s-1.33< 1.33.9.1-r6
- k3s-static< 1.35.2.1-r4
- k3s-static-1.32< 1.32.13.1-r7
Wolfi12 products
- k3s< 1.35.2.1-r4
- k3s-1.32< 1.32.13.1-r7
- k3s-1.33< 1.33.9.1-r6
- k3s-static< 1.35.2.1-r4
- k3s-static-1.32< 1.32.13.1-r7
Debian1 product
- nats-serverAll versions (No fix recorded) | < 2.12.6-1
Github.com/nats-io1 product
- nats-serverAll versions (No fix recorded)
Github.com/nats-io/nats-server1 product
- v2< 2.11.15 | ≥ 2.12.0-RC.1, < 2.12.6
Linuxfoundation1 product
- nats-server< 2.11.15 | ≥ 2.12.0, < 2.12.6
Nats-io1 product
- nats-server< 2.11.15 | ≥ 2.12.0-RC.1, < 2.12.6
Ubuntu1 product
- nats-serverAll versions (No fix recorded)
8 vendors · 46 products
References
15 links- github.com/nats-io/nats-server/security/advisories/GHSA-x6g4-f6q3-fqvvX Refsource CONFIRMREPORTAdvisoryWEBMitigationVendor Advisory
- advisories.nats.io/CVE/secnote-2026-14.txtX Refsource MISCREPORTAdvisoryWEBMitigationVendor Advisory
