CVE-2026-56810 PUBLISHED

mint buffers an entire chunked response chunk in memory in Mint.HTTP1.decode_body/5

Assigner: EEF
Reserved: 23.06.2026 Published: 06.07.2026 Updated: 07.07.2026

Allocation of Resources Without Limits or Throttling vulnerability in elixir-mint mint (Mint.HTTP1 module) allows a denial of service via an oversized chunked transfer-encoded response.

This vulnerability is associated with program files lib/mint/http1.ex and program routines 'Elixir.Mint.HTTP1':decode_body/5, 'Elixir.Mint.HTTP1':add_body_to_buffer/2.

When Mint decodes a chunked HTTP response body, it accumulates each partial fragment of the current chunk in the connection's data_buffer (an unbounded iolist) via add_body_to_buffer/2 and does not emit the data to the caller until the full declared chunk length has been received. The chunk size is taken directly from the server and parsed with no upper bound, so a malicious or compromised server can announce one enormous chunk (for example a size line of 7FFFFFFF, about 2 GiB) and then send the body bytes slowly without ever completing the chunk. The client buffers every received byte while it waits for a completion that never arrives, and because no data responses are produced until the chunk finishes, a caller that otherwise streams large content-length bodies safely gains no protection. An unauthenticated remote server (reachable whenever a client follows redirects, fetches user-supplied URLs, or processes webhooks) can drive the client's memory arbitrarily high and trigger an out-of-memory condition.

This issue affects mint: from 0.5.0 before 1.9.1.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS Score: 8.7

Product Status

Vendor elixir-mint
Product mint
Versions Default: unaffected
  • affected from 0.5.0 to 1.9.1 (excl.)
Vendor elixir-mint
Product mint
Versions Default: unaffected
  • affected from c575d819d39ebf7e9b77ec24584a5ffbb11c844e to 193ce714907d16e8adc4ab3c40e4f0c2f045b2a6 (excl.)

Credits

  • Peter Ullrich finder
  • Andrea Leopardi remediation developer
  • Jonatan Männchen / EEF analyst
  • Eric Meadows-Jönsson analyst

References

Problem Types

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

Impacts

  • CAPEC-130 Excessive Allocation