GHSA-q8x4-x7mp-5vg2

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Source
https://github.com/advisories/GHSA-q8x4-x7mp-5vg2
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-q8x4-x7mp-5vg2/GHSA-q8x4-x7mp-5vg2.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-q8x4-x7mp-5vg2
Aliases
Published
2026-05-05T21:46:09Z
Modified
2026-05-05T22:14:10.498322Z
Severity
  • 8.7 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N CVSS Calculator
Summary
Plug.Cowboy vulnerable to unauthenticated remote DoS via HTTP/2 `:scheme` atom-table exhaustion
Details

Summary

An unauthenticated remote denial-of-service vulnerability in Plug.Cowboy.Conn allows any attacker who can reach an HTTPS Plug.Cowboy listener via HTTP/2 to permanently exhaust the BEAM atom table and crash the entire Erlang VM.

Am I Affected?

All users running plug_cowboy with HTTP/2 may be affected, this includes Phoenix applications. If another HTTP adapter such as Bandit is used, then the consuming project is not affected. If the HTTP/2 endpoint is exposed directly (without a proxy) then the project will be affected. If a proxy is in use then it depends on the proxy configuration. Many proxies use HTTP/1.1 internally, and would be unaffected.

Impact

The vulnerability will allow crashing the Erlang VM (BEAM) via atom exhaustion.

Mitigation

Users are advised to update to plug_cowboy v2.8.1 to mitigate this issue.

Credits

Plug.Cowboy thanks Peter Ullrich for finding and responsibly disclosing this vulnerability.

Database specific 
{
    "github_reviewed": true,
    "severity": "HIGH",
    "github_reviewed_at": "2026-05-05T21:46:09Z",
    "nvd_published_at": "2026-04-27T14:16:47Z",
    "cwe_ids": [
        "CWE-770"
    ]
}
References

Affected packages

Hex / plug_cowboy

Package

Name
plug_cowboy
Purl
pkg:hex/plug_cowboy

Affected ranges

Type
SEMVER
Events
Introduced
2.0.0
Fixed
2.8.1

Affected versions

2.*
2.0.0
2.0.1
2.0.2
2.1.0
2.1.1
2.1.2
2.1.3
2.2.0
2.2.1
2.2.2
2.3.0
2.4.0
2.4.1
2.5.0
2.5.1
2.5.2
2.6.0
2.6.1
2.6.2
2.7.0
2.7.1
2.7.2
2.7.3
2.7.4
2.7.5
2.8.0

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-q8x4-x7mp-5vg2/GHSA-q8x4-x7mp-5vg2.json"