Answer in brief
CVE-2026-56813 records a Low severity (CVSS 2.1) vulnerability in Cookie attribute injection in Plug.Conn.Cookies.encode/2. The current sources do not mark it as known exploited. The current feed maps elixir-plug/plug (generic), elixir-plug/plug (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 2.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps elixir-plug/plug (generic), elixir-plug/plug (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| elixir-plug/pluggeneric | >=0.1.0 <1.16.6 || >=1.17.0 <1.17.4 || >=1.18.0 <1.18.5 || >=1.19.0 <1.19.5 || >=1.20.0 <1.20.3 | 1.16.6, 1.17.4, 1.18.5, 1.19.5, 1.20.3 |
| elixir-plug/pluggeneric | >=f26876aa67aaeb38e616638aa3efbcc2fe2906a5 <* | * |
Published upstream
Jul 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 10, 2026
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.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2026-56813 records a Low severity (CVSS 2.1) vulnerability in Cookie attribute injection in Plug.Conn.Cookies.encode/2. The current sources do not mark it as known exploited. The current feed maps elixir-plug/plug (generic), elixir-plug/plug (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 2.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps elixir-plug/plug (generic), elixir-plug/plug (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| elixir-plug/pluggeneric | >=0.1.0 <1.16.6 || >=1.17.0 <1.17.4 || >=1.18.0 <1.18.5 || >=1.19.0 <1.19.5 || >=1.20.0 <1.20.3 | 1.16.6, 1.17.4, 1.18.5, 1.19.5, 1.20.3 |
| elixir-plug/pluggeneric | >=f26876aa67aaeb38e616638aa3efbcc2fe2906a5 <* | * |
Published upstream
Jul 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 10, 2026
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.
Quoted source text, attributed separately from HOL analysis.