Resource exhaustion in Lin-Snow Ech0
CVE-2026-79661
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L.
EPSS exploit prediction
EPSS: 0.004 (35.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 35th percentile — 35.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.002
Affected products
Weakness classification (CWE)
References
- github.com/lin-snow/Ech0/security/advisories/GHSA-pj6q-4vq4-r8cg (vendor-advisory)
- www.vulncheck.com/advisories/ech0-before-unauthenticated-fav-count-modification (third-party-advisory)
Frequently asked questions
- What is CVE-2026-79661?
- CVE-2026-79661 is a medium-severity vulnerability in Lin-Snow Ech0, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 6.5/10. Published 2026-08-25.
- How severe is CVE-2026-79661?
- Medium severity. CVSS v3 base score is 6.5 out of 10.