Allocation of Resources Without Limits or Throttling vulnerability in elixir-mint Mint allows attacker-controlled HTTP/2 servers to exhaust memory in a Mint client via PUSH_PROMISE flooding.
In lib/mint/http2.ex, Mint.HTTP2.decodepushpromiseheadersandaddresponse/5 inserts a :reservedremote entry into conn.streams for every promised stream ID. The neighbouring Mint.HTTP2.assertvalidpromisedstreamid/2 only verifies that the promised ID is even and not already present; clientsettings.maxconcurrentstreams is not consulted at promise time. The concurrency cap is only checked when the response HEADERS for the promised stream arrive, so a server that emits PUSH_PROMISE frames and withholds the matching HEADERS never trips that check.
HTTP/2 server push is accepted by default (clientsettings.enablepush defaults to true). A single long-lived HTTP/2 connection to a hostile server lets that server pin one conn.streams entry per PUSH_PROMISE frame it sends, with no upper bound, until the client process runs out of memory.
This issue affects mint: from 0.2.0 before 1.9.0.
{
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48862.json",
"unresolved_ranges": [
{
"source": "AFFECTED_FIELD",
"extracted_events": [
{
"introduced": "65c6394d05a1b8aa4a7461708c3aa173e8d7a5cf"
},
{
"fixed": "70b97b6a5209fb288b0e04d8e657dda26c59de67"
}
]
}
],
"cwe_ids": [
"CWE-770"
],
"cna_assigner": "EEF"
}