Weakness Type (CWE)

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

CAPEC

CVSS 4.0 Score

6.3

MEDIUM

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

Vulnerability description

Allocation of resources without limits vulnerability in elixir-mint mint allows a remote HTTP/2 server to exhaust memory on the client host and cause a denial of service.

The Mint.HTTP2.handle_continuation/3 function in lib/mint/http2.ex accumulates the header-block fragment carried by each HTTP/2 CONTINUATION frame into a growing conn.headers_being_processed nesting, one level deeper per frame, and only releases it when a frame with the END_HEADERS flag arrives. The only guard on this accumulator is Mint.HTTP2.assert_header_block_within_max_size/2, which sums the byte size of the fragments received so far. Because a CONTINUATION frame is permitted by the protocol to carry a zero-length payload, an unbounded chain of zero-length CONTINUATION frames adds no bytes to the running total, never trips the size cap, and never emits END_HEADERS, yet each frame still nests the accumulator one level deeper.

A malicious HTTP/2 server (reachable directly, via an attacker-controlled redirect, via SSRF, or via a man-in-the-middle) can open a stream by sending a HEADERS frame without END_HEADERS and then stream zero-length CONTINUATION frames indefinitely. Client memory grows one cons cell per frame received; sustained bandwidth from the peer drives the BEAM node running the Mint client to memory exhaustion and eventual out-of-memory termination.

This issue affects mint: from 0.1.0 before 1.9.2.

Affected

pkg:hex/mint

Module Source File Routine
Mint.HTTP2 lib/mint/http2.ex Mint.HTTP2.handle_continuation/3
Mint.HTTP2.assert_header_block_within_max_size/2
Status Type Version Changes / Fixed in
affected semver ⓘ 0.1.0 < 1.9.2

pkg:github/elixir-mint/mint

Module Source File Routine
Mint.HTTP2 lib/mint/http2.ex Mint.HTTP2.handle_continuation/3
Mint.HTTP2.assert_header_block_within_max_size/2
Status Type Version Changes / Fixed in
affected git ⓘ 596ca43045 < 5779de1666

References

Credits

  • Finder: zx (Jace)
  • Remediation developer: Andrea Leopardi
  • Remediation reviewer: Eric Meadows-Jönsson
  • Analyst: Jonatan Männchen / EEF

CVE record as JSON:  GET /cves/CVE-2026-59246.json
OSV record as JSON:  GET /osv/EEF-CVE-2026-59246.json