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CVE PROGRAM SOURCE RECORD8.2 High

CVE-2026-91043

HPACK-indexed cookie fields in Mint HTTP/2 responses bypass max_header_list_size and exhaust client memory

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Status
Published
Published
Updated
Assigning organization
EEF

Description

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 1.10.2.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

elixir-mint mint

Default version status: unaffected

  • 1.1.0 to < 1.10.2affected
pkg:hex/mint

elixir-mint mint

Default version status: unaffected

  • 8e0e04680476f90f9f68db4dfeabcbe66dabfc4d to < *affected
pkg:github/elixir-mint/mint

References