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CVE-2026-31814

Yamux remote Panic via malformed WindowUpdate credit

No known exploitation. EPSS puts it in the 48th percentile. Fixed in 0.13.9.

CVSS 3.17.5HighEPSS percentile48th0.6% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
No public exploit knownFix0.13.9Upgrade to this build

Published Updated Sources: CVE.org, NVD, GitHub

NVD CVE.org

What to do

Find your product and version, then upgrade to the build on the right.

  • Libp2p Rust-yamuxAffected: >= 0.13.0, < 0.13.9Upgrade to: not statedStated by: CVE record
  • Crates.io YamuxAffected: ≥ 0.13.0, < 0.13.9Upgrade to: 0.13.9Stated by: GitHub advisory
  • Protocol YamuxAffected: ≥ 0.13.0, < 0.13.9Upgrade to: 0.13.9Stated by: NVD

Versions as the sources state them. Full version matrix after sign-in

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What it is

From the CVE record

Yamux is a stream multiplexer over reliable, ordered connections such as TCP/IP. From 0.13.0 to before 0.13.9, a specially crafted WindowUpdate can cause arithmetic overflow in send-window accounting, which triggers a panic in the connection state machine. This is remotely reachable over a normal network connection and does not require authentication. This vulnerability is fixed in 0.13.9.

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS48th
CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

No public exploit or proof of concept found in the sources we track.

EPSS

0.6% chance of exploitation activity in the next 30 days, which ranks it in the 48th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

5 events over 6 days, from the signal feeds we watch.

  1. Patch availablerecord updated
  2. Publishedweakness classified, att&ck mapped

Affected products

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Scored 7.5 by NVD.

How it is reached

  • Attack Vector NetworkExploitable remotely over the network without any special conditions
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required NoneNo authentication required — anyone can exploit this
  • User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality NoneNo confidentiality impact
  • Integrity NoneNo integrity impact
  • Availability HighTotal denial of service — the component is completely unavailable

Weaknesses

ATT&CK techniques

Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.

Sources

References in the record

And 3 more references. See all after sign-in

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