absinthe-graphql vulnerabilities and threats

CVE-2026-42793 is a high-severity vulnerability in absinthe-graphql absinthe versions from 1.5.0 before 1.10.2. It allows unauthenticated denial of service via exhaustion of the Erlang VM atom table when parsing attacker-controlled GraphQL SDL documents. The vulnerability arises because Absinthe's SDL parser converts many unique names into atoms without limits, and atoms are never garbage collected, leading to a fixed-size atom table exhaustion and node crash. Any application that parses untrusted GraphQL SDL input is vulnerable, such as schema-upload endpoints or federation gateways. No official patch or remediation guidance is currently confirmed.

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.

Inefficient Algorithmic Complexity vulnerability in absinthe-graphql absinthe allows unauthenticated denial of service via quadratic fragment-name uniqueness validation. 'Elixir.Absinthe.Phase.Document.Validation.UniqueFragmentNames':run/2 iterates over all fragments and for each one calls duplicate?/2, which evaluates Enum.count(fragments, &(&1.name == name)) — a full linear scan of the fragment list. The result is O(N²) comparisons per document, where N is the number of fragment definitions supplied by the caller. Because input.fragments is built directly from the GraphQL query body, N is fully attacker-controlled. A minimum-size fragment definition is roughly 16 bytes, so a ~1 MB document carries ~60,000 fragments and forces ~3.6 × 10⁹ comparisons inside this single validation phase. No authentication, schema knowledge, or special configuration is required. This issue affects absinthe: from 1.2.0 before 1.10.2.