CVE-2026-79658
Unauthenticated DoS via oversized Accept-Language header in Ech0
Is CVE-2026-79658 being exploited?
Not confirmed. CVE-2026-79658 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.29% probability of exploitation in the next 30 days.
How severe is CVE-2026-79658?
CVE-2026-79658 is rated High with a CVSS score of 8.7. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-79658?
Yes. A fix has been recorded for CVE-2026-79658. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-79658 affect?
CVE-2026-79658 affects Ech0 < 5.0.1, Go web servers using Ech0 i18n middleware, golang.org/x/text language parser. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-79658?
Upgrade Ech0 to 5.0.1; rate-limit or reject oversized Accept-Language headers
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated attacker can send large Accept-Language headers that trigger quadratic-time parsing, consuming CPU and causing denial of service across cores.
Patch when possible
- affected< 5.0.1
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.