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Not in CISA KEV

CVE-2026-79661 Ech0

CVE-2026-79661 is a CWE-770 vulnerability in github.com/lin-snow/Ech0. A fix is available for github.com/lin-snow/Ech0 — see the affected versions and patch details below.

Ech0 before 4.7.3 Unauthenticated fav_count Modification

Also known asGHSA-pj6q-4vq4-r8cgGO-2026-5541
Published
Aug 25, 2026
Updated
Sep 2, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Sep 19, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

  • CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-79661.

EPSS Exploitation Probability

via FIRST.org ↗
0.2%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs16th percentile — riskier than 16% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

1 pkg affected
🐹github.com/lin-snow/Ech0

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

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

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐹Gogithub.com/lin-snow/Ech0all versions1.4.8-0.20260503035905-cecc2c19b590go get github.com/lin-snow/Ech0@v1.4.8-0.20260503035905-cecc2c19b590

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/lin-snow/Ech0, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update github.com/lin-snow/Ech0 to 1.4.8-0.20260503035905-cecc2c19b590 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-79661 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-79661 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2026-79661. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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.
O3 Security · Impact-Aware SCA

Is CVE-2026-79661 in your dependencies?

O3 Security finds CVE-2026-79661 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

CVE-2026-79661: Ech0 | O3 Security