Vulnerability · Published Sep 4, 2026 · Assigned by EEF
CVE-2026-82729Quadratic chunk-size parsing in Mint.HTTP1.Parse allows CPU-exhaustion DoS
Medium 6.3
In plain English
A medium-severity security flaw in mint from elixir-mint. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 45% of all known vulnerabilities).
Official description
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 products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| elixir-mint | mint | 1.9.3 – before 1.10.0 |
| elixir-mint | mint | fc7d16538db7e40b56ed489f08683225cb0197fa – before bd2a4e7513594997c140cfef9fe0e968712fb588 |
Weakness: CWE-407 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N