CVE-2026-59152Network attack vector

Server file disclosure via trace attachment injection

Published Jul 6, 2026 · Updated Jul 6, 2026

Path traversal in LangSmith SDK TracingMiddleware before 0.8.18 allows remote authenticated users to read server-local files via HTTP. An unvalidated tracing-propagation field injects attachment attributes, while an incompatible-type check fails to block the background tracing thread from opening and uploading the named file. Triggering the read can be unauthenticated, but obtaining its contents requires trace-read access to the fixed destination workspace and exposes only files readable by the server process.

CVSS severity7.7
High
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in LangSmith SDK TracingMiddleware before 0.8.18 allows remote authenticated users to read server-local files via HTTP. An unvalidated tracing-propagation field injects attachment attributes, while an incompatible-type check fails to block the background tracing thread from opening and uploading the named file. Triggering the read can be unauthenticated, but obtaining its contents requires trace-read access to the fixed destination workspace and exposes only files readable by the server process.

The record

CVE
CVE-2026-59152
Published
Jul 6, 2026
Updated
Jul 6, 2026
Vendor
LangChain
Product
LangSmith SDK
Classifications
CWE-843, CWE-346, CWE-22, T1005
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 6, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 6, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.8.18

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

LangChain · LangSmith SDKversion=< 0.8.18

Published CVSS scores

7.7GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
5.0LangChain maintainer advisoryCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-843Access of Resource Using Incompatible Type ('Type Confusion')
CWE-346Origin Validation Error
CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1005Data from Local System

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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