CVE-2026-48776 — langgraph-sdk
MEDIUMCVE-2026-48776 is a medium-severity (CVSS 4.2) Path Traversal vulnerability in langgraph-sdk. A fix is available for langgraph-sdk — see the affected versions and patch details below.
LangGraph SDK has unsafe URL path construction
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-48776.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-48776 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
langgraph-sdkReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Summary
langgraph-sdk constructs HTTP request paths for resource operations by interpolating caller-supplied identifier values into URL templates. Without sanitization of those values, identifiers that contain characters with special meaning in URL paths could cause the resulting request to address a different resource (and potentially a different resource type) than the SDK method's call site indicates. In deployments where the SDK receives identifier values that originate from untrusted sources, this could result in unintended access, modification, or deletion of resources beyond the calling user's authorization scope.
This issue is most consequential in deployments that:
- forward end-user-supplied values directly into SDK identifier parameters without first validating them against an expected format (such as a UUID), and
- rely on URL-prefix-based authorization at an upstream layer (reverse proxy, edge gateway, WAF), where the authorization decision is made on the SDK call's intended path rather than on the final delivered request path.
There have no evidence of this behavior being triggered in the wild. This change is intended to reduce the surface available when caller-supplied identifier values originate from untrusted sources.
Affected users / systems
You may be affected if you:
- use
langgraph-sdk(Python) to address resources by identifier, and - pass identifier values into SDK methods that originate from end-user input, untrusted third-party callers, or any source that does not validate identifier format before the SDK call.
Applications that validate identifier values (for example, by parsing them as UUIDs and rejecting anything that does not parse) before passing them to SDK methods are not affected. Validated UUIDs round-trip through the SDK request path unchanged.
Impact
- Potential unintended access, modification, or deletion of resources via SDK methods called for a different resource type, when caller-supplied identifier values are not validated.
- In deployments with prefix-based authorization at an upstream layer, the authorization decision and the final delivered request path may diverge.
- Confidentiality: disclosure of resource content beyond the authorization scope of the calling user.
- Integrity: modification or deletion of resources beyond the authorization scope of the calling user.
Patches / mitigation
The SDK now applies path-segment encoding to identifier values before they are interpolated into request URL templates. After this change, identifier values that contain characters with special meaning in URL paths are transmitted as encoded byte sequences and routed to the resource the SDK method's call site indicates.
Compatibility
Identifier values that match the standard UUID format, or any other format that contains only characters safe to transmit unencoded in URL path segments, round-trip through the SDK request path unchanged. Applications that already validate identifier inputs see no behavioral change.
Operational guidance
- Validate identifier values (typically as UUIDs) at the boundary where untrusted input enters the application, before passing them to SDK methods.
- For deployments relying on URL-prefix-based authorization upstream of LangGraph, prefer authorization at the LangGraph server layer or on parsed-and-validated request paths rather than on raw URL prefixes.
LangSmith / hosted deployments note
This issue affects the SDK that runs in caller applications. The LangGraph server runtime, including LangSmith-hosted deployments, receives ordinary HTTP requests on documented routes and is not itself affected by this issue. Applications that consume LangSmith-hosted services via langgraph-sdk and pass untrusted identifier values to SDK methods should upgrade.
First reported by: pucagit (CyStack).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | langgraph-sdk | all versions | 0.3.15pip install --upgrade 'langgraph-sdk==0.3.15' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for langgraph-sdk, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update langgraph-sdk to 0.3.15 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-48776 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-48776 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-48776. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-48776 in your dependencies?
O3 Security finds CVE-2026-48776 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.