CVE-2026-54892

Source
https://cve.org/CVERecord?id=CVE-2026-54892
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-54892.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-54892
Aliases
Published
2026-06-23T12:31:12.629Z
Modified
2026-07-15T01:49:13.313556662Z
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: quadratic-time decoding of nested query/body parameters enables denial of service
Details

Inefficient algorithmic complexity in Plug's nested-parameter decoder allows an unauthenticated remote attacker to cause denial of service. Plug.Conn.Query.decode/4 (and Plug.Conn.Query.decode_each/2) parse query strings and application/x-www-form-urlencoded request bodies. When a key contains many bracketed segments such as a[a][a][a]=1, the decoder walks the brackets and, for each of the N levels, performs a map operation keyed on an ever-growing binary prefix of the key, hashing the full byte range at each step. The total decode cost is therefore quadratic in the number of nesting levels.

With the default Plug.Parsers.URLENCODED body limit of 1,000,000 bytes, a single request can carry roughly 333,000 nesting levels and saturate a BEAM scheduler for minutes. A small number of concurrent requests can saturate all schedulers and render a Plug-based server unresponsive. No authentication or knowledge of application routes is required.

This vulnerability is associated with program files lib/plug/conn/query.ex and program routines Plug.Conn.Query.decode/4, Plug.Conn.Query.decodeeach/2, Plug.Conn.Query.splitkeys/6, Plug.Conn.Query.insertkeys/3, and Plug.Conn.Query.finalizepointer/2.

This issue affects plug from 1.15.0 before 1.15.5, 1.16.4, 1.17.2, 1.18.3, and 1.19.3.

Database specific
{
    "cwe_ids": [
        "CWE-407"
    ],
    "cna_assigner": "EEF",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54892.json",
    "unresolved_ranges": [
        {
            "source": "AFFECTED_FIELD",
            "extracted_events": [
                {
                    "introduced": "1.15.0"
                },
                {
                    "fixed": "1.15.5"
                },
                {
                    "introduced": "1.16.0"
                },
                {
                    "fixed": "1.16.4"
                },
                {
                    "introduced": "1.17.0"
                },
                {
                    "fixed": "1.17.2"
                },
                {
                    "introduced": "1.18.0"
                },
                {
                    "fixed": "1.18.3"
                },
                {
                    "introduced": "1.19.0"
                },
                {
                    "fixed": "1.19.3"
                },
                {
                    "introduced": "712b875d3442c765d8d37e546ffd5ad9f8afcc55"
                },
                {
                    "fixed": "*"
                }
            ]
        },
        {
            "source": "CPE_FIELD",
            "extracted_events": [
                {
                    "introduced": "1.15.0"
                },
                {
                    "fixed": "1.15.5"
                },
                {
                    "introduced": "1.16.0"
                },
                {
                    "fixed": "1.16.4"
                },
                {
                    "introduced": "1.17.0"
                },
                {
                    "fixed": "1.17.2"
                },
                {
                    "introduced": "1.18.0"
                },
                {
                    "fixed": "1.18.3"
                },
                {
                    "introduced": "1.19.0"
                },
                {
                    "fixed": "1.19.3"
                }
            ]
        },
        {
            "source": "DESCRIPTION",
            "extracted_events": [
                {
                    "introduced": "1.15.0"
                },
                {
                    "fixed": "1.15.5"
                }
            ]
        }
    ]
}
References

Affected packages

Git / github.com/elixir-plug/plug

Affected ranges

Type
GIT
Repo
https://github.com/elixir-plug/plug
Events
Database specific
{
    "source": "REFERENCES"
}

Database specific

source
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-54892.json"