# GO-2026-5981 - Ech0: ParseAcceptLanguage `_` separator bypass enables ~70x CPU amplification via Accept-Language…

Source: https://junglewise.ai/threats/go-2026-5981-ech0-parseacceptlanguage-separator-bypass-enables-70x-cpu-70328a97  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-17  
License: CC BY 4.0 with a link back

Severity: info · Published 2026-07-17

Ech0: ParseAcceptLanguage `_` separator bypass enables ~70x CPU amplification via Accept-Language header in i18n.Middleware in github.com/lin-snow/ech0

Technologies: [github.com/lin-snow/ech0 (Go)](https://junglewise.ai/threats/technologies/github-com-lin-snow-ech0). Vendors: [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is This vulnerability exploited in the wild?** No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.

**How severe is This vulnerability?** Informational severity, published 17 July 2026.

**Which products and versions are affected?** github.com/lin-snow/ech0 (Go) SEMVER:introduced=0.

**Is there a fix for This vulnerability?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**Am I affected?** Check whether you run github.com/lin-snow/ech0 (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.

## Affected products

- github.com/lin-snow/ech0 (Go) SEMVER:introduced=0

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