GHSA-2p26-p43x-fhp8
Fix: elixir-mint/mint@b662d12GHSA-2p26-p43x-fhp8 is a CWE-770 vulnerability in mint. O3 Security confirms whether GHSA-2p26-p43x-fhp8 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
mint: Unbounded CONTINUATION/HEADERS frame accumulation (CONTINUATION flood)
Real-World Exposure
mintReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Hex packages — download data is not available via public APIs for these ecosystems.
Description
Summary
Mint's HTTP/2 client accumulates CONTINUATION header-block fragments into a per-connection buffer with no cap on size or frame count. A malicious or compromised HTTP/2 server can drive the client's memory to arbitrary size by streaming an endless chain of CONTINUATION frames after a HEADERS frame that omits END_HEADERS, causing memory exhaustion and BEAM process death. A single connection to an attacker-controlled HTTP/2 endpoint is sufficient.
Details
When Mint's HTTP/2 receive path observes a HEADERS frame without the END_HEADERS flag, 'Elixir.Mint.HTTP2':handle_headers/3 parks the unparsed header-block fragment in conn.headers_being_processed. Every subsequent CONTINUATION frame on that stream is then appended to the accumulator by 'Elixir.Mint.HTTP2':handle_continuation/3.
Nothing in the receive path bounds this accumulator: there is no per-stream size cap, no CONTINUATION frame-count cap, and max_header_list_size is only enforced on outgoing requests (its default is :infinity, and the only enforcement helper inspects server_settings for request encoding, never inbound header blocks). Each CONTINUATION payload can be up to the peer-advertised SETTINGS_MAX_FRAME_SIZE, so the attacker can grow headers_being_processed to arbitrary size at line rate.
PoC
- Stand up a raw TCP server that speaks the HTTP/2 handshake.
- After the client's request
HEADERSarrives, respond with aHEADERSframe on stream 1 withflags = 0(noEND_HEADERS, noEND_STREAM) and an empty header-block fragment. - Stream
CONTINUATIONframes on stream 1, each withflags = 0and a payload up toSETTINGS_MAX_FRAME_SIZE. Never setEND_HEADERS. - The client's process memory grows linearly with the flood and the BEAM process eventually crashes with OOM.
Impact
Remote, unauthenticated denial-of-service against any process using Mint as an HTTP/2 client against an untrusted or attacker-influenced server. A single connection is sufficient to drive memory to arbitrary size and crash the BEAM process. The default Mint configuration is vulnerable; no client-side opt-in is required. Scored CVSS v4.0 8.2 (HIGH).
Workarounds
Restrict Mint to HTTP/1 on connections to untrusted servers by passing protocols: [:http1] to 'Elixir.Mint.HTTP':connect/4. This avoids the vulnerable HTTP/2 receive path entirely, at the cost of losing HTTP/2 for those connections.
Resources
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💧Hex | mint | all versions | 1.9.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mint. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update mint to 1.9.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-2p26-p43x-fhp8 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-2p26-p43x-fhp8 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-2p26-p43x-fhp8. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-2p26-p43x-fhp8 in your dependencies?
O3 detects GHSA-2p26-p43x-fhp8 across Hex dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.