Vulnerability · Published Aug 25, 2026 · Assigned by VulnCheck

CVE-2026-79661Ech0 before 4.7.3 Unauthenticated fav_count Modification

Medium 6.5

In plain English

A medium-severity resource allocation without limits in Ech0 from lin-snow. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.5Medium

Exploit odds (30 days)0.4%top 62.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

Ech0 through 4.5.6 registers the PUT /api/echo/like/:id endpoint on the public router group without authentication or rate limiting. Unauthenticated attackers can increment the fav_count counter of any echo (including private echoes) by supplying its UUID, which can be harvested from the public GET /api/echo/page feed. Repeated requests are accepted without deduplication, each triggering a database write and a four-key cache invalidation, allowing attackers to inflate popularity metrics and amplify load on the database and cache. Fixed in 4.7.3.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Go	github.com/lin-snow/Ech0	1.4.8-0.20260503035905-cecc2c19b590	GHSA-pj6q-4vq4-r8cg
Go	github.com/lin-snow/ech0	1.4.8-0.20260503035905-cecc2c19b590	GO-2026-5541

Affected products (as reported)

Vendor	Product	Versions
lin-snow	Ech0	0 – before 4.7.3

Weakness: CWE-770 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

References

GitHub Security Advisory (GHSA-pj6q-4vq4-r8cg) vendor-advisory
VulnCheck Advisory: Ech0 before 4.7.3 Unauthenticated fav_count Modification third-party-advisory