elixir-mint 0.1.0/1.9.1 HTTP/2 lib/mint/http2.ex handle_continuation zero allocation of resources

Summaryinfo

A vulnerability identified as problematic has been detected in elixir-mint mint 0.1.0/1.9.1. The impacted element is the function handle_continuation of the file lib/mint/http2.ex of the component HTTP/2 Handler. The manipulation of the argument zero leads to allocation of resources. This vulnerability is referenced as CVE-2026-59246. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability was found in elixir-mint mint 0.1.0/1.9.1 and classified as problematic. This issue affects the function handle_continuation of the file lib/mint/http2.ex of the component HTTP/2 Handler. The manipulation of the argument zero 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. The summary by CVE is:

Allocation of resources without limits vulnerability in elixir-mint mint allows a remote HTTP/2 server to exhaust memory on the client host and cause a denial of service. The Mint.HTTP2.handle_continuation/3 function in lib/mint/http2.ex accumulates the header-block fragment carried by each HTTP/2 CONTINUATION frame into a growing conn.headers_being_processed nesting, one level deeper per frame, and only releases it when a frame with the END_HEADERS flag arrives. The only guard on this accumulator is Mint.HTTP2.assert_header_block_within_max_size/2, which sums the byte size of the fragments received so far. Because a CONTINUATION frame is permitted by the protocol to carry a zero-length payload, an unbounded chain of zero-length CONTINUATION frames adds no bytes to the running total, never trips the size cap, and never emits END_HEADERS, yet each frame still nests the accumulator one level deeper. A malicious HTTP/2 server (reachable directly, via an attacker-controlled redirect, via SSRF, or via a man-in-the-middle) can open a stream by sending a HEADERS frame without END_HEADERS and then stream zero-length CONTINUATION frames indefinitely. Client memory grows one cons cell per frame received; sustained bandwidth from the peer drives the BEAM node running the Mint client to memory exhaustion and eventual out-of-memory termination. This issue affects mint: from 0.1.0 before 1.9.2.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-59246 since 07/04/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

Upgrading to version 1.9.2 eliminates this vulnerability.

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Productinfo

Vendor

• elixir-mint

Name

• mint

Version

• 0.1.0
• 1.9.1

Website

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

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