Is CVE-2026-58436 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-58436 being exploited in the wild.

How severe is CVE-2026-58436?

High severity, with a CVSS score of 4, published 21 July 2026.

Which products and versions are affected?

Gitea < 1.27.0; code.gitea.io/gitea (Go) < 1.27.0, SEMVER:introduced=0,fixed=1.27.0; gitea.dev (Go) SEMVER:introduced=0,fixed=1.27.0.

Is there a fix for CVE-2026-58436?

Yes. code.gitea.io/gitea (Go): upgrade to 1.27.0 or later; gitea.dev (Go): upgrade to 1.27.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-58436 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-58436?

Check whether you run Gitea, code.gitea.io/gitea (Go) or gitea.dev (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-58436: Gitea quadratic-time DoS in Locale middleware via Accept-Language header

Q: Which products and versions are affected?

Gitea < 1.27.0; code.gitea.io/gitea (Go) < 1.27.0, SEMVER:introduced=0,fixed=1.27.0; gitea.dev (Go) SEMVER:introduced=0,fixed=1.27.0.

Q: Is there a fix for CVE-2026-58436?

Yes. code.gitea.io/gitea (Go): upgrade to 1.27.0 or later; gitea.dev (Go): upgrade to 1.27.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-58436 attacked?

It is attacked over the network, in a network appliance.

Q: Am I affected by CVE-2026-58436?

Check whether you run Gitea, code.gitea.io/gitea (Go) or gitea.dev (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-58436 · Severity: high · CVSS 4 · Published 2026-07-21

Gitea, a popular self-hosted Git service, is vulnerable to a denial-of-service attack that can be triggered by unauthenticated users. By sending a specially crafted web request with a malicious language header, an attacker can force the server to consume excessive CPU resources. This can lead to significant performance degradation or a complete service outage for all users.

Technologies: Gitea, code.gitea.io/gitea (Go), gitea.dev (Go). Vendors: Gitea, Go.

Quick answers

Is CVE-2026-58436 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-58436 being exploited in the wild.
How severe is CVE-2026-58436?: High severity, with a CVSS score of 4, published 21 July 2026.
Which products and versions are affected?: Gitea < 1.27.0; code.gitea.io/gitea (Go) < 1.27.0, SEMVER:introduced=0,fixed=1.27.0; gitea.dev (Go) SEMVER:introduced=0,fixed=1.27.0.
Is there a fix for CVE-2026-58436?: Yes. code.gitea.io/gitea (Go): upgrade to 1.27.0 or later; gitea.dev (Go): upgrade to 1.27.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-58436 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-58436?: Check whether you run Gitea, code.gitea.io/gitea (Go) or gitea.dev (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

code.gitea.io/gitea (Go): upgrade to 1.27.0 or later
```
go get code.gitea.io/gitea@v1.27.0
```
gitea.dev (Go): upgrade to 1.27.0 or later
```
go get gitea.dev@v1.27.0
```

Technical details

The Gitea Locale middleware calls golang.org/x/text/language.ParseAcceptLanguage on raw Accept-Language headers without prior validation. While the underlying Go library contains a guard against quadratic-time complexity (CVE-2022-32149) by limiting '-' characters, it fails to account for '_' characters which are aliased to '-' during parsing. An unauthenticated attacker can send a 1 MiB header containing many '_' separators to bypass the guard and trigger O(N²) behavior in the parser's scanner. This allows a small number of concurrent requests to saturate server CPU. The vulnerability is fixed in Gitea version 1.27.0 by implementing a limit on the number of separators allowed in the header.

Affected products

Gitea Gitea < 1.27.0

Identifiers

CVE-2026-58436
GHSA-fw57-jgch-pgf3
GO-2026-6055

Timeline

2026-07-13: advisory: Initial GitHub Advisory published
2026-07-21: disclosed: Full advisory details released
2026-07-21: patched: Vulnerability addressed in version 1.27.0

References

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