CVE-2026-42794 — absinthe_plug
Fix: absinthe-graphql/absinthe_plug@23a0d56CVE-2026-42794 is a Cross-site Scripting (XSS) vulnerability in absinthe_plug. No vendor fix is recorded yet; mitigation options are listed below.
Reflected XSS via backslash bypass in GraphiQL js_escape in absinthe_plug
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-42794.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-42794 can be triaged on real exposure rather than presence alone.
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 Security finds CVE-2026-42794 across Hex dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.