# CVE-2026-25750: LangSmith Studio has URL Parameter Injection Vulnerability that Enables Token Theft via Malicious baseUrl

> Attackers can steal authentication tokens via malicious links, enabling account takeover and unauthorized access to LangSmith resources.

- **Severity:** High 8.5 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 4 Mar 2026
- **Updated:** 5 Mar 2026

## What is CVE-2026-25750?

CVE-2026-25750 is a high-severity vulnerability in langchain-ai helm, published on 4 Mar 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Langchain Helm Charts are Helm charts for deploying Langchain applications on Kubernetes. Prior to langchain-ai/helm version 0.12.71, a URL parameter injection vulnerability existed in LangSmith Studio that could allow unauthorized access to user accounts through stolen authentication tokens. The vulnerability affected both LangSmith Cloud and self-hosted deployments. Authenticated LangSmith users who clicked on a specially crafted malicious link would have their bearer token, user ID, and workspace ID transmitted to an attacker-controlled server. With this stolen token, an attacker could impersonate the victim and access any LangSmith resources or perform any actions the user was authorized to perform within their workspace. The attack required social engineering (phishing, malicious links in emails or chat applications) to convince users to click the crafted URL. The stolen tokens expired after 5 minutes, though repeated attacks against the same user were possible if they could be convinced to click malicious links multiple times. The fix in version 0.12.71 implements validation requiring user-defined allowed origins for the baseUrl parameter, preventing tokens from being sent to unauthorized servers. No known workarounds are available. Self-hosted customers must upgrade to the patched version.

Weakness: CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component)

## Which versions are affected by CVE-2026-25750?

It affects 1 product.


Products: Langchain Langsmith.

## How do I fix CVE-2026-25750?

No fix has been published for CVE-2026-25750 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-25750 being exploited?

There is no known exploitation of CVE-2026-25750 in the wild and no public exploit code.

## Other vulnerabilities in langchain-ai helm

- [CVE-2026-40190](https://insights.sbomify.com/CVE-2026-40190/): LangSmith Client SDKs has Prototype Pollution in langsmith-sdk via Incomplete `__proto__` Guard in Internal lodash `set()` (medium 5.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-25750 and fix it if it is affected.

What it is: CVE-2026-25750 is a high-severity vulnerability in langchain-ai helm, published on 4 Mar 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-25750 in the wild and no public exploit code.

Affected product: langchain-ai helm. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-25750/ (Markdown: https://insights.sbomify.com/CVE-2026-25750/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-25750
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-25750
- OSV: https://osv.dev/vulnerability/CVE-2026-25750

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-25750/
Summaries are generated and may contain mistakes; the official description above is the record.