HPACK-indexed cookie fields in Mint HTTP/2 responses bypass max_header_list_size and exhaust client memory
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.
CVE-2026-91043
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-91043
mint
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
mint
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"cpes": [
"cpe:2.3:a:elixir-mint:mint:*:*:*:*:*:*:*:*"
],
"repo": "https://github.com/elixir-mint/mint",
"vendor": "elixir-mint",
"modules": [
"'Elixir.Mint.HTTP2'"
],
"product": "mint",
"versions": [
{
"status": "affected",
"version": "1.1.0",
"lessThan": "1.10.2",
"versionType": "semver"
}
],
"packageURL": "pkg:hex/mint",
"packageName": "mint",
"programFiles": [
"lib/mint/http2.ex"
],
"collectionURL": "https://repo.hex.pm",
"defaultStatus": "unaffected",
"programRoutines": [
{
"name": "'Elixir.Mint.HTTP2':stream/2"
},
{
"name": "'Elixir.Mint.HTTP2':decode_hbf_and_add_responses/5"
},
{
"name": "'Elixir.Mint.HTTP2':join_cookie_headers/1"
}
]
},
{
"cpes": [
"cpe:2.3:a:elixir-mint:mint:*:*:*:*:*:*:*:*"
],
"repo": "https://github.com/elixir-mint/mint",
"vendor": "elixir-mint",
"modules": [
"'Elixir.Mint.HTTP2'"
],
"product": "mint",
"versions": [
{
"status": "affected",
"changes": [
{
"at": "c7895cb022196c77ec35570c8e873a84393ff4b8",
"status": "unaffected"
},
{
"at": "65a0d61c9eab6b0dedac809de7212515bf506250",
"status": "unaffected"
}
],
"version": "8e0e04680476f90f9f68db4dfeabcbe66dabfc4d",
"lessThan": "*",
"versionType": "git"
}
],
"packageURL": "pkg:github/elixir-mint/mint",
"packageName": "elixir-mint/mint",
"programFiles": [
"lib/mint/http2.ex"
],
"collectionURL": "https://github.com",
"defaultStatus": "unaffected",
"programRoutines": [
{
"name": "'Elixir.Mint.HTTP2':stream/2"
},
{
"name": "'Elixir.Mint.HTTP2':decode_hbf_and_add_responses/5"
},
{
"name": "'Elixir.Mint.HTTP2':join_cookie_headers/1"
}
]
}
]- Related CVEs
- CVE-2026-91043
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #3419 · Revision 1
- Added to Heist Feed
- Publisher date