GHSA-g586-ccqf-7x4r
Fix: elixir-mint/mint@70b97b6GHSA-g586-ccqf-7x4r is a CWE-770 vulnerability in mint. O3 Security confirms whether GHSA-g586-ccqf-7x4r is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
mint: Unbounded streams map growth via PUSH_PROMISE without follow-up HEADERS
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for GHSA-g586-ccqf-7x4r.
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 accepts PUSH_PROMISE frames from any server it connects to and inserts every promised stream into a per-connection map without consulting max_concurrent_streams. A malicious or compromised HTTP/2 server can flood the client with PUSH_PROMISE frames and withhold the matching response HEADERS, pinning one map entry per frame indefinitely until the client process runs out of memory.
Details
'Elixir.Mint.HTTP2':handle_push_promise/3 in lib/mint/http2.ex dispatches every inbound PUSH_PROMISE frame to 'Elixir.Mint.HTTP2':decode_push_promise_headers_and_add_response/5, which inserts a :reserved_remote entry into conn.streams for the promised ID. The only validation applied is that the promised ID is even and not already present; client_settings.max_concurrent_streams is not consulted at promise time.
The concurrency cap is only checked when the response HEADERS for the promised stream arrive. A server that emits PUSH_PROMISE frames and never sends the matching HEADERS never trips that check, and the existing tally counts only streams in open states, not :reserved_remote entries.
HTTP/2 server push is accepted by default (client_settings.enable_push defaults to true), so no application opt-in is required. A single long-lived HTTP/2 connection to a hostile server lets it pin one conn.streams entry per PUSH_PROMISE frame, with no upper bound.
PoC
- Stand up a raw TCP HTTP/2 server that completes the handshake and ACKs the client's
SETTINGS. - Wait for the client's request
HEADERSand capture its odd stream ID. - Send a flood of
PUSH_PROMISEframes (flags = END_HEADERS) associated with the captured stream, each promising a fresh even stream ID and carrying a minimal HPACK-encoded header block. - Never send the matching response
HEADERSfor any of the promised IDs. - The client's
conn.streamsmap grows by one entry perPUSH_PROMISEframe (~148 bytes/entry); memory grows linearly 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. Server push is on by default, so no application code change can prevent it short of disabling push or upgrading. Affected populations include outbound HTTP/2 clients in web backends, webhook delivery systems, scrapers, federated and proxy components, and any service that follows redirects to third-party HTTP/2 origins.
Workarounds
Disable HTTP/2 server push on connections to untrusted servers by passing client_settings: [enable_push: false] to 'Elixir.Mint.HTTP':connect/4. Mint will then reject any inbound PUSH_PROMISE frame with a PROTOCOL_ERROR before the vulnerable code path is reached.
Resources
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💧Hex | mint | ≥ 0.2.0&&< 1.9.0 | 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-g586-ccqf-7x4r 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-g586-ccqf-7x4r 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-g586-ccqf-7x4r. 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-g586-ccqf-7x4r in your dependencies?
O3 detects GHSA-g586-ccqf-7x4r across Hex dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.