CVE-2026-42794
Fix: absinthe-graphql/absinthe_plug@23a0d56CVE-2026-42794 is a security vulnerability in absinthe_plug. O3 Security confirms whether CVE-2026-42794 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Reflected XSS via backslash bypass in GraphiQL js_escape in absinthe_plug
Real-World Exposure
absinthe_plugReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Hex packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💧Hex | absinthe_plug | ≥ 1.2.0 | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for absinthe_plug. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of absinthe_plug has shipped for CVE-2026-42794 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-42794 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-42794. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-42794 in your dependencies?
O3 detects CVE-2026-42794 across Hex dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.