CVE-2026-82729

Summary

Inefficient Algorithmic Complexity vulnerability in elixir-mint mint allows a remote HTTP server to exhaust CPU on the client host and cause a denial of service.

parse_hex_prefix/2 in lib/mint/http1/parse.ex folds each hex digit of a chunked response's chunk-size field into an arbitrary-precision accumulator with acc * 16 + digit and imposes no limit on the digit count. Because the accumulator grows without bound, the multiplication is not constant time and one pass over N digits costs O(N squared). handle_data/2 prepends conn.buffer and re-parses from the start on every socket message, so a server that dribbles the digits out in small packets makes the client pay that cost repeatedly. A run of roughly 512,000 hex digits costs over ten seconds of CPU in a single pass, measured on stock defaults. The parser reaches this state after a valid status line and a complete, valid header section, so an intermediary inspecting only headers sees an ordinary 200 response.

This issue affects mint: from 1.9.3 before 1.10.0.

Affected Software

VendorProductVersion RangeStatus
elixir-mintmint1.9.3 < 1.10.0affected
elixir-mintmintfc7d16538db7e40b56ed489f08683225cb0197fa < bd2a4e7513594997c140cfef9fe0e968712fb588affected

Weaknesses

  • CWE-407: CWE-407 Inefficient Algorithmic Complexity

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: poc
    • Automatable: no
    • Technical Impact: partial

Additional References

References