CVE-2020-26892
First published: Fri Nov 06 2020(Updated: )
## Problem Description NATS nats-server through 2020-10-07 has Incorrect Access Control because of how expired credentials are handled. The NATS accounts system has expiration timestamps on credentials; the <https://github.com/nats-io/jwt> library had an API which encouraged misuse and an `IsRevoked()` method which misused its own API. A new `IsClaimRevoked()` method has correct handling and the nats-server has been updated to use this. The old `IsRevoked()` method now always returns true and other client code will have to be updated to avoid calling it. The CVE identifier should cover any application using the old JWT API, where the nats-server is one of those applications. ## Affected versions #### JWT library * all versions prior to 1.1.0 * fixed after nats-io/jwt PR 103 landed (2020-10-06) #### NATS Server * Version 2 prior to 2.1.9 + 2.0.0 through and including 2.1.8 are vulnerable. * fixed with nats-io/nats-server PRs 1632, 1635, 1645 ## Impact Time-based credential expiry did not work. ## Workaround Have credentials which only expire after fixes can be deployed. ## Solution Upgrade the JWT dependency in any application using it. Upgrade the NATS server if using NATS Accounts.
Credit: cve@mitre.org cve@mitre.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| go/github.com/nats-io/nats-server/v2 | <2.1.9 | 2.1.9 |
| go/github.com/nats-io/jwt | <1.1.0 | 1.1.0 |
| Linuxfoundation Nats-server | <2.1.9 | |
| Fedoraproject Fedora | =33 | |
| <2.1.9 | ||
| =33 |
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Reference Links
- https://github.com/nats-io/jwt/security/advisories/GHSA-4w5x-x539-ppf5
- https://nvd.nist.gov/vuln/detail/CVE-2020-26892
- https://github.com/nats-io/nats-server/commit/1e08b67f08e18cd844dce833a265aaa72500a12f
- https://advisories.nats.io/CVE/CVE-2020-26892.txt
- https://github.com/nats-io/nats-server/commits/master
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VT67XCLIIBYRT762SVFBYFFTQFVSM3SI/
- https://www.openwall.com/lists/oss-security/2020/11/02/2
- https://github.com/nats-io/jwt/commit/e11ce317263cef69619fc1ca743b195d02aa1d8a
- https://pkg.go.dev/vuln/GO-2022-0380
- https://github.com/advisories/GHSA-4w5x-x539-ppf5 (Advisory)
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VT67XCLIIBYRT762SVFBYFFTQFVSM3SI/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VT67XCLIIBYRT762SVFBYFFTQFVSM3SI
Frequently Asked Questions
What is the severity of CVE-2020-26892?
The severity of CVE-2020-26892 is critical with a CVSS score of 9.8.
How does CVE-2020-26892 impact NATS nats-server?
CVE-2020-26892 impacts NATS nats-server through 2020-10-07 by allowing incorrect access control due to how expired credentials are handled.
Which software versions are affected by CVE-2020-26892?
The affected software versions are nats-server/v2 up to 2.1.9 and jwt up to 1.1.0.
Where can I find more information about CVE-2020-26892?
More information about CVE-2020-26892 can be found in the references section of the advisory.
How can I mitigate the vulnerability CVE-2020-26892?
To mitigate the vulnerability CVE-2020-26892, it is recommended to update nats-server/v2 to version 2.1.9 and jwt to version 1.1.0.
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