CVE-2026-54892
Plug: quadratic-time decoding of nested query/body parameters enables denial of service
Description
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.decode_each/2, Plug.Conn.Query.split_keys/6, Plug.Conn.Query.insert_keys/3, and Plug.Conn.Query.finalize_pointer/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.
INFO
Published Date :
June 23, 2026, 1:16 p.m.
Last Modified :
June 23, 2026, 3:44 p.m.
Remotely Exploit :
Yes !
Source :
6b3ad84c-e1a6-4bf7-a703-f496b71e49db
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 4.0 | HIGH | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | ||||
| CVSS 4.0 | HIGH | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db |
Solution
- Update Plug to version 1.15.5 or later.
- Update Plug to version 1.16.4 or later.
- Update Plug to version 1.17.2 or later.
- Update Plug to version 1.18.3 or later.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-54892.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-54892 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-54892
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-54892 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-54892 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 23, 2026
Action Type Old Value New Value Added Reference https://github.com/elixir-plug/plug/security/advisories/GHSA-j43x-5hjq-rgxf Added SSVC {'id': 'CVE-2026-54892', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-23T13:03:58.893269Z'} -
New CVE Received by 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Jun. 23, 2026
Action Type Old Value New Value Added Affected [{'cpes': ['cpe:2.3:a:elixir-plug:plug:*:*:*:*:*:*:*:*'], 'repo': 'https://github.com/elixir-plug/plug', 'vendor': 'elixir-plug', 'modules': ["'Elixir.Plug.Conn.Query'"], 'product': 'plug', 'versions': [{'status': 'affected', 'version': '1.15.0', 'lessThan': '1.15.5', 'versionType': 'semver'}, {'status': 'affected', 'version': '1.16.0', 'lessThan': '1.16.4', 'versionType': 'semver'}, {'status': 'affected', 'version': '1.17.0', 'lessThan': '1.17.2', 'versionType': 'semver'}, {'status': 'affected', 'version': '1.18.0', 'lessThan': '1.18.3', 'versionType': 'semver'}, {'status': 'affected', 'version': '1.19.0', 'lessThan': '1.19.3', 'versionType': 'semver'}], 'packageURL': 'pkg:hex/plug', 'packageName': 'plug', 'programFiles': ['lib/plug/conn/query.ex'], 'collectionURL': 'https://repo.hex.pm', 'defaultStatus': 'unaffected', 'programRoutines': [{'name': "'Elixir.Plug.Conn.Query':decode/4"}, {'name': "'Elixir.Plug.Conn.Query':decode_each/2"}, {'name': "'Elixir.Plug.Conn.Query':split_keys/6"}, {'name': "'Elixir.Plug.Conn.Query':insert_keys/3"}, {'name': "'Elixir.Plug.Conn.Query':finalize_pointer/2"}]}, {'cpes': ['cpe:2.3:a:elixir-plug:plug:*:*:*:*:*:*:*:*'], 'repo': 'https://github.com/elixir-plug/plug', 'vendor': 'elixir-plug', 'modules': ["'Elixir.Plug.Conn.Query'"], 'product': 'plug', 'versions': [{'status': 'affected', 'changes': [{'at': 'c317d08fdcf96e17931f7419275b2b8c4bf3e951', 'status': 'unaffected'}, {'at': '9c5d37c440eaae92869eed7c014c47266744fadb', 'status': 'unaffected'}, {'at': 'd737eb236f17e31a36290e39f9ef3cd86a1343bd', 'status': 'unaffected'}, {'at': 'd4e5568392a4b29e545b91e12e87d6098f976145', 'status': 'unaffected'}, {'at': 'a61124aa625d819a218fb07f90afbac8aa85eb0e', 'status': 'unaffected'}], 'version': '712b875d3442c765d8d37e546ffd5ad9f8afcc55', 'lessThan': '*', 'versionType': 'git'}], 'packageURL': 'pkg:github/elixir-plug/plug', 'packageName': 'elixir-plug/plug', 'programFiles': ['lib/plug/conn/query.ex'], 'collectionURL': 'https://github.com', 'defaultStatus': 'unaffected', 'programRoutines': [{'name': "'Elixir.Plug.Conn.Query':decode/4"}, {'name': "'Elixir.Plug.Conn.Query':decode_each/2"}, {'name': "'Elixir.Plug.Conn.Query':split_keys/6"}, {'name': "'Elixir.Plug.Conn.Query':insert_keys/3"}, {'name': "'Elixir.Plug.Conn.Query':finalize_pointer/2"}]}] Added Description 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.decode_each/2, Plug.Conn.Query.split_keys/6, Plug.Conn.Query.insert_keys/3, and Plug.Conn.Query.finalize_pointer/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. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-407 Added Reference https://cna.erlef.org/cves/CVE-2026-54892.html Added Reference https://github.com/elixir-plug/plug/commit/9c5d37c440eaae92869eed7c014c47266744fadb Added Reference https://github.com/elixir-plug/plug/commit/a61124aa625d819a218fb07f90afbac8aa85eb0e Added Reference https://github.com/elixir-plug/plug/commit/c317d08fdcf96e17931f7419275b2b8c4bf3e951 Added Reference https://github.com/elixir-plug/plug/commit/d4e5568392a4b29e545b91e12e87d6098f976145 Added Reference https://github.com/elixir-plug/plug/commit/d737eb236f17e31a36290e39f9ef3cd86a1343bd Added Reference https://github.com/elixir-plug/plug/security/advisories/GHSA-j43x-5hjq-rgxf Added Reference https://osv.dev/vulnerability/EEF-CVE-2026-54892