What’s Vulnerable › Vulnerabilities

CVE-2020-26521

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-11-06 · updated 2026-06-17
• Weakness: CWE-476

Description

The JWT library in NATS nats-server before 2.1.9 allows a denial of service (a nil dereference in Go code).

Affected products

• Fedoraproject Fedora: 33
• nats-io nats-server: before 2.1.9 — fixed in 2.1.9

How to fix

Upgrade to a fixed version: nats-io nats-server 2.1.9. Check the vendor advisory for mitigations.

References

• http://www.openwall.com/lists/oss-security/2020/11/02/2
• https://github.com/nats-io/nats-server/commits/master
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VT67XCLIIBYRT762SVFBYFFTQFVSM3SI/
• http://www.openwall.com/lists/oss-security/2020/11/02/2
• https://github.com/nats-io/nats-server/commits/master
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VT67XCLIIBYRT762SVFBYFFTQFVSM3SI/

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