VulnerabilityPublished 28 Oct 2026

CVE-2026-118667: Unencoded identifiers in LangGraph SDK v3 streaming can redirect authenticated GET requests

Affects langgraph-sdkSource GCVE Database

Authoritative record:CVE-2026-118667· Medium 4.3

Not known to be exploited · CVSS 4.3 Medium : upgrade to 0.4.6 when convenient.

Data as of 28 Oct 2026, 22:12 UTC

CVSS 3.1 base score

4.3Medium

How severe the flaw is on the 0–10 CVSS scale.

Patch: Available – fixed in 0.4.6, 1.2.14

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 28 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade langgraph-sdk to 0.4.6; langgraph to 1.2.14.

Affected software

Product	Affected	Fixed in
PyPIlanggraph-sdk	Affected >=0.4.0 <0.4.6	Fixed in 0.4.6
PyPIlanggraph	Affected >=1.2.3 <1.2.14	Fixed in 1.2.14

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

### Summary The LangGraph Python SDK v3 streaming client interpolates caller-supplied `thread_id` and `assistant_id` values into request paths without encoding them at four synchronous and asynchronous call sites. Relative path segments can therefore redirect an authenticated GET request to another path on the same configured server. ### Details The affected `get_tree` and `_fetch_state` implementations build request paths from raw identifiers rather than passing each identifier through the SDK's existing `_quote_path_param` helper. HTTP path normalization can collapse values containing relative segments before dispatch while retaining the client's authentication headers. `langgraph-sdk` versions 0.4.0 through 0.4.5 are affected. The v3 stream module is not present in the 0.3.x release line. `RemoteGraph` v3 streaming in `langgraph` 1.2.3 and later is also affected when used with a vulnerable `langgraph-sdk` version. It passes `config["configurable"]["thread_id"]` into `threads.stream(...)`, and its dependency range permits affected SDK versions. ### Impact An application is affected only if it passes attacker-controlled text as a streaming `thread_id` or `assistant_id`. In that configuration, an attacker may select another readable path on the configured server and cause the SDK to return that response to the application. Through `thread_id`, the attacker can also control the query string, for example by targeting `/store/items?namespace=...&key=...`; `assistant_id` controls only the path. The affected requests are GET operations, so this issue does not provide a write primitive. The LangGraph Platform is not exposed to this issue. ### Remediation Upgrade `langgraph-sdk` to version 0.4.6 or later. The fix encodes `assistant_id` in `get_tree` and `thread_id` in `_fetch_state` with `_quote_path_param` in both synchronous and asynchronous stream modules. If you use `RemoteGraph`, also upgrade `langgraph` to version 1.2.14 or later, which requires `langgraph-sdk>=0.4.6`.

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #6OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks…
Implementation · Input Validation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174).
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V12.3.1 (opens in a new tab)
Attack patterns
Path Traversal (opens in a new tab)
Using Slashes and URL Encoding Combined to Bypass Validation Logic (opens in a new tab)
Manipulating Web Input to File System Calls (opens in a new tab)
Using Escaped Slashes in Alternate Encoding (opens in a new tab)
Using Slashes in Alternate Encoding (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

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Affected software

Description

WeaknessesCWE-22

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