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CVE-2026-86099

Chainlit through 2.12.0 Path Traversal via socket.io sessionId

No known exploitation. EPSS puts it in the 48th percentile. No fix published yet.

CVSS 3.18.2HighEPSS percentile48th0.6% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
No public exploit knownFixNone yetNo fix or workaround published

Published Updated Sources: CVE.org, NVD

NVD CVE.org

What to do

No fixed build or workaround is published yet. Limit exposure and watch for a patch.

  • ChainlitAffected: ≤ 2.12.0Upgrade to: after 2.12.0Stated by: CVE record

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

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What it is

From the CVE record

Chainlit through 2.12.0 fails to validate the client-supplied socket.io sessionId parameter, allowing unauthenticated attackers to traverse filesystem paths by injecting absolute or relative path sequences. Attackers can craft malicious sessionId values that escape the upload directory and recursively delete arbitrary directories accessible to the service process.

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 0 days, from the signal feeds we watch.

  1. Publishedweakness classified, att&ck mapped, record updated, record updated

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:L/A:H

Scored 8.2 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 LowData modification is possible but limited in scope or consequence
  • 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 2 more references. See all after sign-in

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