CVE-2026-43967

Description

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.

Weakness classification

• 6b3ad84c-e1a6-4bf7-a703-f496b71e49db: CWE-407

Primary references

• 6b3ad84c-e1a6-4bf7-a703-f496b71e49db — Patch, Third Party Advisory
• 6b3ad84c-e1a6-4bf7-a703-f496b71e49db — Patch
• 6b3ad84c-e1a6-4bf7-a703-f496b71e49db — Exploit, Vendor Advisory
• 6b3ad84c-e1a6-4bf7-a703-f496b71e49db — Third Party Advisory