CVE-2026-56813

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2026-56813
Improper Neutralization of Parameter/Argument Delimiters vulnerability in elixir-plug plug allows an attacker to inject or override HTTP cookie attributes. The Plug.Conn.Cookies.encode/2 function in lib/plug/conn/cookies.ex builds the Set-Cookie response header by interpolating the cookie value and its path, domain, same_site, and extra attributes directly into the header without neutralizing the ; delimiter that separates cookie attributes. An application that places attacker-controlled data into a cookie value or attribute (for example via Plug.Conn.put_resp_cookie/4 when reflecting a username or preference) lets an attacker inject a ; to append or override cookie attributes (such as Domain and Path scope, or dropping the Secure and HttpOnly flags), enabling cookie tossing and session fixation. Carriage return, line feed, and null bytes are rejected by Plug.Conn header validation, so HTTP response splitting is not possible, but attribute injection through ; is not prevented. This issue affects plug: from 0.1.0 before 1.16.6, from 1.17.0 before 1.17.4, from 1.18.0 before 1.18.5, from 1.19.1 before 1.19.5, and from 1.20.0 before 1.20.3.
CVSS

No CVSS.

References
Link Resource
https://cna.erlef.org/cves/CVE-2026-56813.html
https://github.com/elixir-plug/plug/commit/149d9ed68fee0b4f77efd1e835ce5d785856697b
https://github.com/elixir-plug/plug/commit/3f00dfad4e20ba88472e315c90a25742bf178f8e
https://github.com/elixir-plug/plug/commit/4167981747fe9ce75f374b94a28861ae950ea992
https://github.com/elixir-plug/plug/commit/a6d1248659022749869963fd302687165ecf8c8b
https://github.com/elixir-plug/plug/commit/eceb8315ce9a31ef784943a95a8624ebd1bc7e06
https://github.com/elixir-plug/plug/commit/f26876aa67aaeb38e616638aa3efbcc2fe2906a5
https://github.com/elixir-plug/plug/security/advisories/GHSA-wpmj-jh88-rpgm
https://osv.dev/vulnerability/EEF-CVE-2026-56813
Configurations

No configuration.

History

24 Oct 2026, 23:10

Type Values Removed Values Added
Summary
  • (es) Vulnerabilidad de neutralización incorrecta de delimitadores de parámetro/argumento en el plug elixir-plug permite a un atacante inyectar o sobrescribir atributos de cookie HTTP. La función Plug.Conn.Cookies.encode/2 en lib/plug/conn/cookies.ex construye el encabezado de respuesta Set-Cookie interpolando el valor de la cookie y sus atributos de ruta, dominio, same_site y extra directamente en el encabezado sin neutralizar el delimitador ’;’ que separa los atributos de la cookie. Una aplicación que coloca datos controlados por el atacante en un valor o atributo de cookie (por ejemplo, a través de Plug.Conn.put_resp_cookie/4 al reflejar un nombre de usuario o preferencia) permite a un atacante inyectar un ’;’ para añadir o sobrescribir atributos de cookie (como el alcance de Dominio y Ruta, o la eliminación de las banderas Secure y HttpOnly), lo que permite el ’cookie tossing’ y la fijación de sesión. El retorno de carro, el salto de línea y los bytes nulos son rechazados por la validación de encabezados de Plug.Conn, por lo que la división de respuesta HTTP no es posible, pero la inyección de atributos a través de ’;’ no se evita. Este problema afecta a plug: desde 0.1.0 antes de 1.16.6, desde 1.17.0 antes de 1.17.4, desde 1.18.0 antes de 1.18.5, desde 1.19.0 antes de 1.19.5, desde 1.20.0 antes de 1.20.3.

24 Sep 2026, 22:17

Type Values Removed Values Added
References
  • {'url': 'https://github.com/elixir-plug/plug/commit/c6575800b2c4e15af1904df87522ca8a23da020c', 'source': '6b3ad84c-e1a6-4bf7-a703-f496b71e49db'}
  • () https://github.com/elixir-plug/plug/commit/149d9ed68fee0b4f77efd1e835ce5d785856697b -
  • () https://github.com/elixir-plug/plug/commit/3f00dfad4e20ba88472e315c90a25742bf178f8e -
  • () https://github.com/elixir-plug/plug/commit/4167981747fe9ce75f374b94a28861ae950ea992 -
  • () https://github.com/elixir-plug/plug/commit/a6d1248659022749869963fd302687165ecf8c8b -
  • () https://github.com/elixir-plug/plug/commit/eceb8315ce9a31ef784943a95a8624ebd1bc7e06 -
  • () https://github.com/elixir-plug/plug/commit/f26876aa67aaeb38e616638aa3efbcc2fe2906a5 -
Summary (en) Improper Neutralization of Parameter/Argument Delimiters vulnerability in elixir-plug plug allows an attacker to inject or override HTTP cookie attributes. The Plug.Conn.Cookies.encode/2 function in lib/plug/conn/cookies.ex builds the Set-Cookie response header by interpolating the cookie value and its path, domain, same_site, and extra attributes directly into the header without neutralizing the ';' delimiter that separates cookie attributes. An application that places attacker-controlled data into a cookie value or attribute (for example via Plug.Conn.put_resp_cookie/4 when reflecting a username or preference) lets an attacker inject a ';' to append or override cookie attributes (such as Domain and Path scope, or dropping the Secure and HttpOnly flags), enabling cookie tossing and session fixation. Carriage return, line feed, and null bytes are rejected by Plug.Conn header validation, so HTTP response splitting is not possible, but attribute injection through ';' is not prevented. This issue affects plug: from 0.1.0 before 1.16.6, from 1.17.0 before 1.17.4, from 1.18.0 before 1.18.5, from 1.19.0 before 1.19.5, from 1.20.0 before 1.20.3. (en) Improper Neutralization of Parameter/Argument Delimiters vulnerability in elixir-plug plug allows an attacker to inject or override HTTP cookie attributes. The Plug.Conn.Cookies.encode/2 function in lib/plug/conn/cookies.ex builds the Set-Cookie response header by interpolating the cookie value and its path, domain, same_site, and extra attributes directly into the header without neutralizing the ; delimiter that separates cookie attributes. An application that places attacker-controlled data into a cookie value or attribute (for example via Plug.Conn.put_resp_cookie/4 when reflecting a username or preference) lets an attacker inject a ; to append or override cookie attributes (such as Domain and Path scope, or dropping the Secure and HttpOnly flags), enabling cookie tossing and session fixation. Carriage return, line feed, and null bytes are rejected by Plug.Conn header validation, so HTTP response splitting is not possible, but attribute injection through ; is not prevented. This issue affects plug: from 0.1.0 before 1.16.6, from 1.17.0 before 1.17.4, from 1.18.0 before 1.18.5, from 1.19.1 before 1.19.5, and from 1.20.0 before 1.20.3.
Information

Published : 2026-07-10 13:16

Updated : 2026-10-24 23:10

NVD link : CVE-2026-56813

Mitre link : CVE-2026-56813

CVE.ORG link : CVE-2026-56813

JSON object : View

Products Affected

No product.

CWE
CWE-141

Improper Neutralization of Parameter/Argument Delimiters