CVE-2026-42794 PUBLISHED

Reflected XSS via backslash bypass in GraphiQL js_escape in absinthe_plug

Assigner: EEF
Reserved: 29.04.2026 Published: 08.05.2026 Updated: 09.05.2026

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.

Metrics

CVSS Vector: 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
CVSS Score: 2.3

Product Status

Vendor absinthe-graphql
Product absinthe_plug
Versions Default: unaffected
  • affected from 1.2.0 to * (excl.)
Vendor absinthe-graphql
Product absinthe_plug
Versions Default: unaffected
  • affected from 26241817cb4b9be4de3f5972c5fba3d36de3d713 to 23a0d5658d32420086711adf4ce8f05febb09963 (excl.)

Affected Configurations

The application must mount Absinthe.Plug.GraphiQL on a route that is reachable by untrusted users. The GraphiQL interface is a developer tool and is typically disabled or restricted in production deployments.

Credits

  • 40826d finder
  • Bryan A. Enders finder
  • Leandro Moreno remediation developer
  • Ben Wilson remediation reviewer

References

Problem Types

  • CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') CWE

Impacts

  • CAPEC-86 XSS Using HTTP Query Strings