CVE-2020-26521 Nil dereference in NATS JWT, DoS of nats-server

What is CVE-2020-26521?

CVE-2020-26521 is a high-severity vulnerability in Fedoraproject Fedora, published on 6 Nov 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

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

Weakness: CWE-476

Which versions are affected by CVE-2020-26521?

5 open source packages ship an affected version, including github.com/nats-io/jwt and github.com/nats-io/nats-server/v2. It affects 2 products.

Products include Fedoraproject Fedora, Linuxfoundation Nats-Server.

How do I fix CVE-2020-26521?

Upgrade github.com/nats-io/jwt to 1.1.0 or later.

Is CVE-2020-26521 being exploited?

There is no known exploitation of CVE-2020-26521 in the wild and no public exploit code.

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• CVE-2024-4577 PHP-CGI OS Command Injection Exploited Critical 9.8
• CVE-2021-39226 Grafana Authentication Bypass Exploited Critical 9.8
• CVE-2019-5544 VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow Exploited Critical 9.8
• CVE-2024-4947 Google Chromium V8 Type Confusion Exploited Critical 9.6
• CVE-2024-4671 Google Chromium Visuals Use-After-Free Exploited Critical 9.6

All Fedoraproject Fedora vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2020-26521, GHSA-h2fg-54x9-5qhq, GHSA-hmm9-r2m2-qg9w, GO-2022-0402, UBUNTU-CVE-2020-26521.