# CVE-2026-79661: Ech0 unauthenticated fav_count modification

Source: https://junglewise.ai/threats/cve-2026-79661-ech0-unauthenticated-fav-count-modification  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-25. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-79661 · Severity: medium · CVSS 6.5 · Published 2026-08-25

Ech0 is a social media feed application. An unprotected endpoint allows anyone on the network to artificially boost the popularity counter of any post without authentication or rate limits. Attackers can damage platform integrity by manipulating trending rankings and overwhelming the database with repeated write requests.

Technologies: [github.com/lin-snow/ech0 (Go)](https://junglewise.ai/threats/technologies/github-com-lin-snow-ech0), [Lin-Snow Ech0](https://junglewise.ai/threats/technologies/ech0). Vendors: [Go](https://junglewise.ai/threats/vendors/go), [Lin-Snow](https://junglewise.ai/threats/vendors/lin-snow).

## Quick answers

**Is CVE-2026-79661 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-79661 being exploited in the wild.

**How severe is CVE-2026-79661?** Medium severity, with a CVSS score of 6.5, published 25 August 2026.

**Which products and versions are affected?** github.com/lin-snow/ech0 (Go) SEMVER:introduced=0,fixed=1.4.8-0.20260503035905-cecc2c19b590; Lin-Snow Ech0 through 4.5.6.

**Is there a fix for CVE-2026-79661?** Yes. github.com/lin-snow/ech0 (Go): upgrade to 1.4.8-0.20260503035905-cecc2c19b590 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-79661 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-79661?** Check whether you run github.com/lin-snow/ech0 (Go) or Lin-Snow Ech0 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/lin-snow/ech0 (Go): upgrade to 1.4.8-0.20260503035905-cecc2c19b590 or later

  ```sh
  go get github.com/lin-snow/ech0@v1.4.8-0.20260503035905-cecc2c19b590
  ```


## Technical details

The PUT /api/echo/like/:id endpoint is registered on the public router group without JWT authentication or rate limiting. The vulnerable LikeEcho handler in internal/repository/echo/echo.go:270 performs no visibility checks and accepts repeated increment requests from the same IP without deduplication. Attackers can harvest post UUIDs from the public GET /api/echo/page feed or via other channels (logs, referer headers, shared drafts) and craft repeated PUT requests to inflate fav_count on any echo, including private echoes. Each request triggers a database UPDATE transaction plus four cache key invalidations, amplifying load on storage and caching layers. The issue is fixed in version 4.7.3 by moving the route to AuthRouterGroup, adding per-user deduplication, and implementing rate limiting middleware.

## Affected products

- lin-snow Ech0 through 4.5.6

## Identifiers

- CVE-2026-79661
- GHSA-pj6q-4vq4-r8cg
- GO-2026-5541

## Timeline

- 2026-05-03: disclosed: GitHub Security Advisory published
- 2026-04: patched: Fixed in version 4.7.3
- 2026-08-25: advisory: CVE-2026-79661 published on NVD

## References

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

## Related threats

- [Ech0 scope bypass in PUT /user endpoint via profile:read token](https://junglewise.ai/threats/cve-2026-79673-ech0-scope-bypass-in-put-user-endpoint-via-profile-read-token)
- [Ech0 authorization bypass in comment panel endpoints](https://junglewise.ai/threats/cve-2026-79672-ech0-authorization-bypass-in-comment-panel-endpoints)
- [Ech0 server-side request forgery in webhook URL validation](https://junglewise.ai/threats/cve-2026-79671-ech0-server-side-request-forgery-in-webhook-url-validation)
- [Ech0 stored cross-site scripting in file upload](https://junglewise.ai/threats/cve-2026-79670-ech0-stored-cross-site-scripting-in-file-upload)
- [Ech0 missing authorization on system log endpoints](https://junglewise.ai/threats/cve-2026-79669-ech0-missing-authorization-on-system-log-endpoints)