CVE-2026-42794: Absinthe plug Cross-Site Scripting Vulnerability

LOW
Advisory Identifier: GHSA-c62g-j346-39v5
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CVSS 6.1
CWE-79
Published
Advisory Summary

CVE-2026-42794 is a LOW (CVSS 6.1) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Absinthe plug libraries in the Hex ecosystem. The issue involves absinthe_plug has a cross-site scripting vulnerability. Remediation is available in the latest vendor maintenance releases.

CVE-2026-42794 at a Glance

CVE Identifier CVE-2026-42794
GHSA Identifier GHSA-c62g-j346-39v5
Severity LOW
CVSS v3.1 Base Score 6.1
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Absinthe plug
Package Ecosystem Hex
Published Date
Last Updated

Security Impact

CVSS: 6.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Changed (S:C)
Confidentiality Low (C:L)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2026-42794

To remediate this vulnerability, upgrade all affected Absinthe plug dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

absinthe_plug fixed: Latest secure release 
Upgrade absinthe_plug to Latest secure release
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for absinthe_plug

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-42794, inspect your project dependencies for Absinthe plug:

inspect dependencies for absinthe_plug

Analyze the terminal output to locate any version of Absinthe plug in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In Absinthe plug, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Improper Neutralization of Input During Web Page Generation (XSS) vulnerability in absinthe-graphql absinthe_plug allows reflected cross-site scripting via the GraphiQL interface. 'Elixir.Absinthe.Plug.GraphiQL':js_escape/1 in lib/absinthe/plug/graphiql.ex escapes single quotes and newlines in the query GET parameter before embedding it in an inline JavaScript string, but does not escape backslashes. An attacker can bypass the escaping by prefixing a quote with a backslash (e.g. \'), breaking out of the string context and executing arbitrary JavaScript in the victim's browser. This issue affects absinthe_plug: from 1.2.0.

CVE-2026-42794 Affected Absinthe plug Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
absinthe_plug
 Hex
≥ 1.2.0
≤ 1.5.9

References

NVD — CVE-2026-42794 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-42794
Absinthe plug Source Repository REPOSITORY
https://github.com/absinthe-graphql/absinthe_plug/issues/275
Security Fix Commit FIX COMMIT
https://github.com/absinthe-graphql/absinthe_plug/commit/23a0d5658d32420086711adf4ce8f05febb09963
cna.erlef.org/cves/cve-2026-42794... WEB
https://cna.erlef.org/cves/CVE-2026-42794.html
Absinthe plug Source Repository REPOSITORY
https://github.com/absinthe-graphql/absinthe_plug
osv.dev/vulnerability/eef-c... WEB
https://osv.dev/vulnerability/EEF-CVE-2026-42794

Frequently Asked Questions

What is CVE-2026-42794?
CVE-2026-42794 is a security vulnerability in Absinthe plug involving absinthe_plug Has a Cross-site Scripting vulnerability under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Absinthe plug versions are affected?
Affected versions include releases prior to current release patches across affected packages: absinthe_plug.
What version fixes CVE-2026-42794?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is absinthe_plug affected?
Yes, absinthe_plug is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2026-42794?
CVE-2026-42794 has a CVSS v3.1 base score of 6.1 (LOW) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
What CWE is associated with CVE-2026-42794?
CVE-2026-42794 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).
How can I check Hex dependencies for CVE-2026-42794?
Run the dependency tree command: 'inspect dependencies for absinthe_plug'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-c62g-j346-39v5",
  "modified" : "2026-06-08T23:12:53Z",
  "published" : "2026-05-08T18:31:35Z",
  "aliases" : [ "CVE-2026-42794" ],
  "summary" : "absinthe_plug Has a Cross-site Scripting vulnerability",
  "details" : "Improper Neutralization of Input During Web Page Generation (XSS) vulnerability in absinthe-graphql absinthe_plug allows reflected cross-site scripting via the GraphiQL interface.\n\n'Elixir.Absinthe.Plug.GraphiQL':js_escape/1 in lib/absinthe/plug/graphiql.ex escapes single quotes and newlines in the query GET parameter before embedding it in an inline JavaScript string, but does not escape backslashes. An attacker can bypass the escaping by prefixing a quote with a backslash (e.g. \\'), breaking out of the string context and executing arbitrary JavaScript in the victim's browser.\n\nThis issue affects absinthe_plug: from 1.2.0.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Hex",
      "name" : "absinthe_plug"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.2.0"
      }, {
        "last_affected" : "1.5.9"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-42794"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/absinthe-graphql/absinthe_plug/issues/275"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/absinthe-graphql/absinthe_plug/commit/23a0d5658d32420086711adf4ce8f05febb09963"
  }, {
    "type" : "WEB",
    "url" : "https://cna.erlef.org/cves/CVE-2026-42794.html"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/absinthe-graphql/absinthe_plug"
  }, {
    "type" : "WEB",
    "url" : "https://osv.dev/vulnerability/EEF-CVE-2026-42794"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-14T13:09:29Z",
    "nvd_published_at" : "2026-05-08T16:16:12Z"
  }
}