CVE-2024-32984 is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in yamux. A fix is available for yamux — see the affected versions and patch details below.
Yamux Memory Exhaustion Vulnerability via Active::pending_frames property
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2024-32984.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2024-32984 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
yamuxReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
Summary
Attack scenario The Rust implementation of the Yamux stream multiplexer uses a vector for pending frames. This vector is not bounded in length. Every time the Yamux protocol requires sending of a new frame, this frame gets appended to this vector. This can be remotely triggered in a number of ways, for example by:
- Opening a new libp2p Identify stream. This causes the node to send its Identify message. Of course, every other protocol that causes the sending of data also works. The larger the response, the more data is enqueued.
- Sending a Yamux Ping frame. This causes a Pong frame to be enqueued.
Under normal circumstances, this queue of pending frames would be drained once they’re sent out over the network. However, the attacker can use TCP’s receive window mechanism to prevent the victim from sending out any data: By not reading from the TCP connection, the receive window will never be increased, and the victim won’t be able to send out any new data (this is how TCP implements backpressure). Once this happens, Yamux’s queue of pending frames will start growing indefinitely. The queue will only be drained once the underlying TCP connection is closed.
Components https://github.com/libp2p/rust-yamux/blob/yamux-v0.13.1/yamux/src/connection.rs#L289
Details
This attack is inspired by the HTTP/2 Rapid Reset Attack (CVE 2023-44487), HTTP/2 Ping Flood (CVE-2019-9512), and the QUIC Path Validation attack (see my blog post: https://seemann.io/posts/2023-12-18-exploiting-quics-path-validation/).
Impact
An attacker can cause a remote node to run out of memory, which will result in the corresponding process getting terminated by the operating system.
Depending on the application protocols running on top of rust-libp2p, higher amplification factors are possible. For example, image a protocol that sends out 10 MB of data as a result of an incoming request. By issuing that request and sending a Yamux stream window update (together ~100-200 bytes), the victim would now enqueue the entire 10 MB into its frame buffer. Any block transfer / sync protocols might be good candidates.
In addition to consuming huge amounts of memory, this attack also drives up the victim's CPU load, such that the allocation of memory at some point becomes CPU-limited.
This was originally submitted by @marteen-seemann to the Ethereum Foundation bug bounty program.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | yamux | ≥ 0.13.0&&< 0.13.2 | 0.13.2cargo update -p yamux --precise 0.13.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for yamux, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update yamux to 0.13.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-32984 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2024-32984 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2024-32984. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2024-32984 in your dependencies?
O3 Security finds CVE-2024-32984 across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.