CVE-2026-43967

Summary

Inefficient Algorithmic Complexity vulnerability in absinthe-graphql absinthe allows unauthenticated denial of service via quadratic fragment-name uniqueness validation. 'Elixir.Absinthe.Phase.Docume

Details

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.

References

• https://cna.erlef.org/cves/CVE-2026-43967.html
• https://github.com/absinthe-graphql/absinthe/commit/223600c520493dcaf95080af552c413099f92c9d
• https://github.com/absinthe-graphql/absinthe/security/advisories/GHSA-9mhv-8h52-q7q2
• https://osv.dev/vulnerability/EEF-CVE-2026-43967