elixir-mint up to 1.10.x HTTP/2 Header Processing lib/mint/http2.ex join_cookie_headers allocation of resources

Summaryinfo

A vulnerability classified as problematic was found in elixir-mint mint up to 1.10.x. Affected by this vulnerability is the function join_cookie_headers of the file lib/mint/http2.ex of the component HTTP2 Header Processing. Such manipulation leads to allocation of resources. This vulnerability is documented as CVE-2026-91043. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in elixir-mint mint up to 1.10.x and classified as problematic. Affected by this issue is the function join_cookie_headers of the file lib/mint/http2.ex of the component HTTP2 Header Processing. The manipulation with an unknown input leads to a allocation of resources vulnerability. Using CWE to declare the problem leads to CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. Impacted is availability. CVE summarizes:

Allocation of Resources Without Limits or Throttling vulnerability in elixir-mint mint allows a malicious HTTP/2 server to exhaust memory on the client host and cause a denial of service. Mint.HTTP2 enforces the client's max_header_list_size setting only on the compressed size of an inbound header block, while RFC 9113 section 6.5.2 defines the limit on the decoded header list. An HPACK indexed field costs one byte on the wire and decodes to a dynamic table entry of up to 4 KB, and join_cookie_headers/1 in lib/mint/http2.ex copies every cookie value of a response into one new binary. A header block under the default 256 KB wire limit therefore makes the client allocate about 1 GB for a single response, and several such responses in one delivery exhaust the memory of the process that owns the connection or of the whole VM. This issue affects mint: from 1.1.0 before 1.11.0.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-91043 since 09/16/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1499 by the MITRE ATT&CK project.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

• elixir-mint

Name

• mint

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10

Website

• Product: https://github.com/elixir-mint/mint/

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