CVE-2026-49754

Summary

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 (HTTP/2 CONTINUATION flood).

When Mint's HTTP/2 receive path observes a HEADERS frame without the END_HEADERS flag, the unparsed header-block fragment is parked in conn.headers_being_processed, and every subsequent CONTINUATION frame on that stream is appended to the accumulator. Nothing in the receive path caps the accumulator: there is no per-stream size limit, no CONTINUATION frame-count limit, and max_header_list_size is only enforced on outgoing requests, never on inbound header blocks (its default is :infinity).

A malicious or compromised HTTP/2 server can stream an endless sequence of CONTINUATION frames (each up to the peer-advertised SETTINGS_MAX_FRAME_SIZE) and drive the client's iolist to arbitrary size, causing memory exhaustion and BEAM process death. A single connection to an attacker-controlled HTTP/2 endpoint is sufficient.

This issue affects mint: from 0.1.0 before 1.9.0.

Affected Software

VendorProductVersion RangeStatus
elixir-mintmint0.1.0 < 1.9.0affected
elixir-mintmint596ca4304504be68939c4929e0831557097962b8 < b662d127d3028b5426c88d4c9cc7fe430491a10baffected

Weaknesses

  • CWE-770: CWE-770 Allocation of Resources Without Limits or Throttling

Workarounds

Restrict Mint to HTTP/1 on connections to untrusted servers by passing protocols: [:http1] to Mint.HTTP.connect/4. This avoids the vulnerable HTTP/2 receive path entirely, at the cost of losing HTTP/2 for those connections.

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: poc
    • Automatable: yes
    • Technical Impact: partial

Additional References

References