absinthe-graphql absinthe up to 1.10.1 algorithmic complexity

Summaryinfo

A vulnerability was found in absinthe-graphql absinthe up to 1.10.1. It has been classified as problematic. Affected by this issue is some unknown functionality. The manipulation leads to algorithmic complexity. This vulnerability is uniquely identified as CVE-2026-43967. The attack is possible to be carried out remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in absinthe-graphql absinthe up to 1.10.1. This issue affects an unknown code block. The manipulation with an unknown input leads to a algorithmic complexity vulnerability. Using CWE to declare the problem leads to CWE-407. An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached. Impacted is availability. The summary by CVE is:

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.

The weakness was disclosed by Peter Ullrich as GHSA-9mhv-8h52-q7q2. The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-43967 since 05/04/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

Upgrading to version 1.10.2 eliminates this vulnerability. Applying the patch 223600c520493dcaf95080af552c413099f92c9d is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-28800). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• absinthe-graphql

Name

• absinthe

Version

• 1.10.0
• 1.10.1

License

• open-source

Website

• Product: https://github.com/absinthe-graphql/absinthe/

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CPE 2.2info

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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