Allocation of Resources Without Limits or Throttling vulnerability in elixir-mint mint allows a malicious HTTP/2 server to make the client hold up to about 16 MiB per connection in frames it should reject, consuming client memory.

Mint.HTTP2.Frame.decode_next/2 in lib/mint/http2/frame.ex compares a frame with the client's max_frame_size (16,384 bytes by default) only once the whole declared payload has arrived. Until then it returns :more, and Mint.HTTP2 keeps every received byte in the connection buffer. A server can declare a frame length of up to 16,777,215 bytes and withhold the last byte, keeping roughly 1,024 times the advertised limit buffered for as long as the connection stays open. The server has to send every byte the client buffers, so there is no amplification, and the buffer stops at the 24-bit frame length limit.

This issue affects mint: from 0.1.0 before 1.11.0.

Project Subscriptions

Vendors Products
Elixir-mint Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.


Workaround

Connect to untrusted origins over HTTP/1 only, with protocols: [:http1] in Mint.HTTP.connect/4, which never runs the HTTP/2 frame decoder. Finch and Req pools use HTTP/1 only unless :http2 is added to their protocols option.

History

Mon, 28 Sep 2026 11:30:00 +0000

Type Values Removed Values Added
Description Allocation of Resources Without Limits or Throttling vulnerability in elixir-mint mint allows a malicious HTTP/2 server to make the client hold up to about 16 MiB per connection in frames it should reject, consuming client memory. Mint.HTTP2.Frame.decode_next/2 in lib/mint/http2/frame.ex compares a frame with the client's max_frame_size (16,384 bytes by default) only once the whole declared payload has arrived. Until then it returns :more, and Mint.HTTP2 keeps every received byte in the connection buffer. A server can declare a frame length of up to 16,777,215 bytes and withhold the last byte, keeping roughly 1,024 times the advertised limit buffered for as long as the connection stays open. The server has to send every byte the client buffers, so there is no amplification, and the buffer stops at the 24-bit frame length limit. This issue affects mint: from 0.1.0 before 1.11.0.
Title Mint HTTP/2 client buffers oversized frames up to 16 MiB before enforcing max_frame_size
First Time appeared Elixir-mint
Elixir-mint mint
Weaknesses CWE-770
CPEs cpe:2.3:a:elixir-mint:mint:*:*:*:*:*:*:*:*
Vendors & Products Elixir-mint
Elixir-mint mint
References
Metrics cvssV4_0

{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N'}


Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: EEF

Published:

Updated: 2026-09-28T11:15:20.657Z

Reserved: 2026-09-15T16:00:01.513Z

Link: CVE-2026-92103

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-09-28T12:17:41.973

Modified: 2026-09-28T14:31:05.267

Link: CVE-2026-92103

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-28T13:00:15Z

Weaknesses