CVE-2026-79661

MEDIUM 6.5

Ech0 before 4.7.3 Unauthenticated fav_count Modification

CVSS Score

6.5

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-770
Vendor	lin-snow
Product	ech0
Published	Aug 25, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

Low

Affected Versions

lin-snow / Ech0

0 < 4.7.3

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/lin-snow/Ech0/security/advisories/GHSA-pj6q-4vq4-r8cg vulncheck.com: https://www.vulncheck.com/advisories/ech0-before-unauthenticated-fav-count-modification

Credits

🔍 adrgs aisafe-bot