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CVE-2021-3127

24
FAUCET Score

CVE-2021-3127 is an Incorrect Access Control vulnerability affecting NATS Server versions prior to 2.2.0 and the JWT library before 2.0.1, caused by mishandled Import Token bindings. This vulnerability carries a High severity CVSS score of 7.5, indicating it is remotely exploitable with low complexity and no user interaction or privileges required, primarily impacting confidentiality. Despite the high confidentiality impact, there is no evidence of active exploitation, nor are public exploit tools available in Metasploit or ExploitDB. Community discussion and media coverage are absent, and its EPSS score suggests a very low probability of exploitation.

Impacted Technologies

VendorProductVersion(s)CPE
>= 2.0.0, < 2.2.0CPE matchmatch criteria
cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*
< 2.0.1CPE matchmatch criteria
cpe:2.3:a:nats:jwt_library:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.46%
Probability of exploitation in next 30 days
EPSS Percentile
70.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0146 is in the 52nd percentile among its peer group of 51,506 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

gopatch availablevia ghsa
Product: github.com/nats-io/jwt/v2Fixed in: 2.0.1

Vendor Advisories (1)

goGHSA-62mh-w5cv-p88ccritical

nats-io/jwt not enforcing checking of Import token permissions

Feb 15, 2022

References

advisories.nats.io / CVE/CVE-2021-3127.txt
ExploitVendor Advisory