VulertSecurity VulertSecurity

Vulnerability Database · Hex · Package report

cowboy: vulnerability history, versions and safety

cowboy is a package in the Hex ecosystem. Vulert records 4 vulnerabilities for it across 34 releases, from May 2026 to Jul 2026. Each vulnerability names the versions it affects, the fixed version to move to, and a workaround where no fix has been published.

i
4 vulnerabilities recorded H1 M1 U2
i
0 with no fix published

Every vulnerability has a patched version to move to.

i
4 in the last 12 months

Most recent disclosure 28 Jul 2026.

See the disclosure history →
i
0 malicious-package vulnerabilities

No published version shipped hostile code.

See all cowboy vulnerabilities

Vulert verdict on cowboy 2.20.0 i

Updated on 23 Oct 2026

Good news: 2.20.0, the version you would install today, has no known vulnerabilities. Older releases do — the table below lists all 4.

Package health score 85/100
  • Security Some issues to review
  • Maintenance Sustainable
  • Popularity Key ecosystem project
  • Community Not enough data

What to do: Stay on 2.20.0 or newer. This can change: a vulnerability disclosed tomorrow can affect 2.20.0 too — Vulert watches the package and alerts you if that happens. Monitor it with Vulert →

  • Current release 2.20.0 — unaffected i
  • Vulnerabilities on record 4 over 1 year · 4 in the last year i
  • Latest disclosure 28 Jul 2026 i
  • Highest CVSS 8.2 i
  • With no published fix 0 i
  • Depended on by 150,742,354 packages i
  • Last release this month i

Version list, release dates, licence and dependants published by hex.pm, refreshed 23 Oct 2026. Licence information is not legal advice.

Concerned about your application's security?

Vulert continues monitoring your dependencies and alerts you when new vulnerabilities are disclosed. No installation and no source-code access required.

01 Versions

Which versions are affected

Every version Vulert tracks for cowboy, newest first, with the vulnerabilities recorded against each one. A version showing none has no vulnerability in the Vulert database — open it for the full picture on that release.

i
Version Released Vulert vulnerabilities Licence Fix published Details
2.20.0 08 Oct 2026 none — — Details →
2.19.0 08 Sep 2026 none — — Details →
2.18.0 28 Jul 2026 none — — Details →
2.17.0 02 Jul 2026 U1 — Yes Details →
2.16.1 11 Jun 2026 U1 — Yes Details →
2.16.0 08 Jun 2026 U1 — Yes Details →
2.15.0 12 May 2026 M1 U1 — Yes Details →
2.14.2 08 Oct 2025 H1 M1 U2 — Yes Details →
2.14.1 01 Oct 2025 H1 M1 U2 — Yes Details →
2.14.0 18 Sep 2025 H1 M1 U2 — Yes Details →
2.13.0 18 Feb 2025 H1 M1 U2 — Yes Details →
2.12.0 14 Mar 2024 H1 M1 U2 — Yes Details →
2.11.0 29 Jan 2024 H1 M1 U2 — Yes Details →
2.10.0 28 Apr 2023 H1 M1 U2 — Yes Details →
2.9.0 12 May 2021 H1 M1 U2 — Yes Details →
2.8.0 30 May 2020 H1 M1 U2 — Yes Details →
2.7.0 16 Oct 2019 H1 M1 U2 — Yes Details →
2.6.3 05 Apr 2019 H1 M1 U2 — Yes Details →
2.6.2 04 Apr 2019 H1 M1 U2 — Yes Details →
2.6.1 28 Nov 2018 H1 M1 U2 — Yes Details →
2.6.0 19 Nov 2018 H1 M1 U2 — Yes Details →
2.5.0 03 Oct 2018 H1 M1 U2 — Yes Details →
2.4.0 02 May 2018 H1 M1 U2 — Yes Details →
2.3.0 06 Apr 2018 H1 M1 U2 — Yes Details →
2.2.2 24 Jan 2018 H1 M1 U2 — Yes Details →
2.2.1 23 Jan 2018 H1 M1 U2 — Yes Details →
2.2.0 13 Dec 2017 H1 M1 U2 — Yes Details →
2.1.0 09 Nov 2017 H1 M1 U2 — Yes Details →
2.0.0 05 Oct 2017 H1 M1 U2 — Yes Details →
1.1.2 06 Feb 2017 M1 — Yes Details →
1.1.1 06 Feb 2017 M1 — Yes Details →
1.1.0 02 Feb 2017 M1 — Yes Details →
1.0.4 17 Nov 2015 M1 — Yes Details →
1.0.3 13 Sep 2015 M1 — Yes Details →
1.0.2 02 Jul 2015 M1 — Yes Details →
1.0.1 02 Jul 2015 M1 — Yes Details →
1.0.0 01 Aug 2014 M1 — Yes Details →

All 37 versions Vulert tracks for this package. Severity counts are the vulnerabilities recorded against that exact release.

02 Disclosure history

How often vulnerabilities are recorded

  • 2026 4

Counted by the year Vulert recorded each vulnerability — the same date the table below shows as disclosed. 4 of the 4 were recorded in the last 12 months.

03 Vulnerabilities

Recorded vulnerabilities for cowboy

The 4 most severe of 4 vulnerabilities recorded for this package

Search all 4 in the database →
Vulnerability Severity Fixed version ↓ Disclosed ↓
CVE-2026-8466: Cowboy Unbounded Buffer Accumulation Vulnerability Leading to Denial of Service 8.2 high 2.15.0 13 May 2026
CVE-2026-8466: Cowboy Package Suffers from Unbounded Buffer Accumulation Leading to Denial of Service 8.2 high 2.15.0 13 May 2026
CVE-2026-65624: Cowboy HTTP/1.1 Max Headers Bypass Leading to Memory Exhaustion 6.9 medium 2.18.0 28 Jul 2026
CVE-2026-43966: cowboy and gun HTTP Request/Response Splitting Vulnerability 6.3 medium 2.16.0 08 Jun 2026

Vulnerability wrong, a fix missing, or a package we should cover? Report it and we will fix the record. Report Vulnerability Provide Feedback

Updated: 23/Oct/2026 · Vulnerabilities in our DB: 524315

Subscribe to Vulert on Telegram
Daily digest of new CVEs, critical and high severity, affected packages and fixes — plus a weekly roundup.
Join the channel →

Questions

About cowboy

Is cowboy safe to use?

Vulert records 4 vulnerabilities for cowboy in Hex: 0 critical, 1 high, 1 medium and 0 low, plus 2 not yet rated. Every one of them has a published fix, so the practical answer is to run a supported release and keep it patched.

What is cowboy's Vulert package health score?

Vulert scores cowboy 85/100, which reads as healthy. The score weighs the vulnerability record (40), maintenance and release cadence (25), adoption from dependents and stars (20) and community signals such as the OpenSSF scorecard and forks (15).

Is the latest version of cowboy affected?

No. 2.20.0, the version you would install today, has no vulnerabilities on record against it. Earlier releases do — the version table above lists each release with what affects it.

How many vulnerabilities does cowboy have?

4 vulnerabilities are recorded for cowboy in the Hex ecosystem: 0 critical, 1 high, 1 medium and 0 low, plus 2 not yet rated. The ledger on this page lists the same counts next to the date of the most recent disclosure.

How often are new cowboy vulnerabilities disclosed?

4 vulnerabilities were recorded for cowboy in the last 12 months, and the oldest entry in this database dates to 13 May 2026. Recency matters more than a lifetime total: it shows how actively new issues are being disclosed for the package you are considering.

Which versions of cowboy are affected?

Each vulnerability on this page lists the affected version range and the fixed version to move to. Open the vulnerability for the version you actually run — fixes are specific to a release line, not to the package as a whole.

How do I monitor cowboy for upcoming vulnerabilities?

Upload the manifest or SBOM for your application at vulert.com/scanner and Vulert keeps checking the cowboy version you actually run against new disclosures, then alerts you when one affects it. There is no installation and no source-code access required.