CVE-2026-79658 lin-snow CVE debrief

Who should care

Organizations using Ech0 before version 5.0.1 should prioritize patching this vulnerability to prevent potential denial of service attacks. Additionally, security teams and administrators responsible for web application security should be aware of this vulnerability and take necessary precautions to mitigate its impact.

Technical summary

Ech0 before 5.0.1 is vulnerable to denial of service attacks due to its i18n middleware's lack of input validation and sanitization for the Accept-Language header. The header is passed unfiltered to go-i18n's NewLocalizer, which can lead to quadratic-time parsing and high CPU consumption with large, specially crafted headers. This can be mitigated by implementing input validation, enforcing a reasonable size limit for the Accept-Language header, and monitoring server performance.

Defensive priority

High-priority defensive actions are recommended due to the HIGH CVSS score of 8.7 and potential for denial of service attacks.

Recommended defensive actions

• Implement input validation and sanitization for the Accept-Language header to prevent large, malicious headers from being processed.
• Enforce a reasonable size limit for the Accept-Language header.
• Monitor server performance and implement rate limiting to mitigate potential denial of service attacks.
• Update to Ech0 version 5.0.1 or later to address the vulnerability.
• Consider implementing a Web Application Firewall (WAF) to detect and prevent suspicious traffic.

Evidence notes

The CVE-2026-79658 issue arises from Ech0's i18n middleware not imposing size or shape limits on the Accept-Language header, which is passed unfiltered to go-i18n's NewLocalizer. This allows for quadratic-time parsing with large headers built from underscore separators, potentially leading to denial of service. The CVE-2022-32149 mitigation in x/text only caps '-' characters, not '_' characters, which are aliased to '-', enabling this vulnerability.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.