# CVE-2026-82729: elixir-mint HTTP/1 parser algorithmic complexity denial of service

Source: https://junglewise.ai/threats/cve-2026-82729-elixir-mint-http-1-parser-algorithmic-complexity-denial-of  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-04. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-82729 · Severity: info · Published 2026-09-04

mint is an HTTP client library for Elixir used by applications to communicate with web services. A malicious HTTP server can send carefully crafted responses that cause the client's CPU to spike and become unresponsive, disrupting application availability and degrading user experience.

Technologies: [Elixir-Mint Mint](https://junglewise.ai/threats/technologies/mint). Vendors: [Elixir-Mint](https://junglewise.ai/threats/vendors/elixir-mint).

## Quick answers

**Is CVE-2026-82729 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-82729 being exploited in the wild.

**How severe is CVE-2026-82729?** Informational severity, published 4 September 2026.

**Which products and versions are affected?** Elixir-Mint Mint 1.9.3 before 1.10.0.

**Is there a fix for CVE-2026-82729?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-82729 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-82729?** Check whether you run Elixir-Mint Mint at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is an algorithmic complexity issue in the parse_hex_prefix/2 function within lib/mint/http1/parse.ex. The parser processes hex digits in chunked HTTP response chunk-size fields using unbounded-precision arithmetic (acc * 16 + digit) with no digit count limit, resulting in O(N²) computational cost for N digits. The handle_data/2 function exacerbates this by prepending conn.buffer and re-parsing from the start on every socket message, causing repeated expensive computations. An attacker can send chunk-size hex digits in small packets over ~512,000 digits to consume over ten seconds of CPU per pass. The attack is network-reachable and requires no authentication; the malicious response looks like a normal 200 HTTP status to intermediaries that only inspect headers.

## Affected products

- elixir-mint mint 1.9.3 before 1.10.0

## Timeline

- 2026-09-04: disclosed

## References

- [https://repo.hex.pm/](https://repo.hex.pm/)
- [https://github.com/](https://github.com/)

## Related threats

- [Mint HTTP request/response smuggling in transfer encoding parsing](https://junglewise.ai/threats/cve-2026-94194-inconsistent-interpretation-of-http-requests-http-request)
- [Elixir Mint HTTP/2 frame buffer exhaustion](https://junglewise.ai/threats/cve-2026-92103-allocation-of-resources-without-limits-or-throttling)
- [Mint HTTP/2 header list memory exhaustion denial of service](https://junglewise.ai/threats/cve-2026-91043-allocation-of-resources-without-limits-or-throttling)
- [Elixir Mint HTTP request smuggling in chunked transfer encoding](https://junglewise.ai/threats/cve-2026-82672-inconsistent-interpretation-of-http-requests-http-request)
- [Elixir Mint HTTP/1 parser denial of service via unbounded buffer](https://junglewise.ai/threats/cve-2026-82728-elixir-mint-http-1-parser-denial-of-service-via-unbounded-buffer)