CVE-2026-23991 go-tuf affected by client DoS via malformed server response
A compromised TUF repository can cause a denial of service in go-tuf clients by sending malformed metadata that triggers a panic before signature validation.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-23991?
CVE-2026-23991 is a medium-severity denial of service vulnerability in theupdateframework go-tuf, published on 22 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
go-tuf is a Go implementation of The Update Framework (TUF). Starting in version 2.0.0 and prior to version 2.3.1, if the TUF repository (or any of its mirrors) returns invalid TUF metadata JSON (valid JSON but not well formed TUF metadata), the client will panic during parsing, causing a denial of service. The panic happens before any signature is validated. This means that a compromised repository/mirror/cache can DoS clients without having access to any signing key. Version 2.3.1 fixes the issue. No known workarounds are available.
Which versions are affected by CVE-2026-23991?
3 open source packages ship an affected version, including github.com/theupdateframework/go-tuf/v2. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/theupdateframework/go-tuf/v2 Go | All versions | 2.3.1 |
github.com/theupdateframework/go-tuf/v2 Go | All versions | 2.3.1 |
github.com/theupdateframework/go-tuf/v2 Go | All versions | 2.3.1 |
Products include Theupdateframework Go-Tuf.
How do I fix CVE-2026-23991?
Upgrade github.com/theupdateframework/go-tuf/v2 to 2.3.1 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-23991 being exploited?
There is no known exploitation of CVE-2026-23991 in the wild and no public exploit code.
Other vulnerabilities in theupdateframework go-tuf
Sources
Also known as AZL-75186, BELL-CVE-2026-23991, CLEANSTART-2026-HN41905, CLEANSTART-2026-JT87240, DEBIAN-CVE-2026-23991, GHSA-846p-jg2w-w324 and 35 more.