{"id":"CVE-2026-118667","kind":"vulnerability","aliases":["CVE-2026-118667","GHSA-3fx2-cqw9-xr3c"],"related":[],"title":"LangGraph: Unencoded identifiers in LangGraph SDK v3 streaming can redirect authenticated GET requests","description":"### Summary\n\nThe 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.\n\n### Details\n\nThe 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.\n\n`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.\n\n`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.\n\n### Impact\n\nAn 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.\n\nThe LangGraph Platform is not exposed to this issue.\n\n### Remediation\n\nUpgrade `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.\n\nIf you use `RemoteGraph`, also upgrade `langgraph` to version 1.2.14 or later, which requires `langgraph-sdk>=0.4.6`.","summary":"The LangGraph Python SDK v3 streaming client puts caller-supplied thread_id and assistant_id values into request paths without encoding them, so relative path segments can redirect an authenticated GET to another readable path on the same server. An attacker who controls those identifiers can read another response on the configured server, and can control the query string through thread_id, but cannot write.","severity":"medium","cvss":4.3,"epss":null,"exploited":false,"exploited_at":null,"products":[{"name":"langgraph-sdk","fixed":["0.4.6"],"affected":">= 0.4.0, < 0.4.6","ecosystem":"pypi"},{"name":"langgraph","fixed":["1.2.14"],"affected":">= 1.2.3, < 1.2.14","ecosystem":"pypi"}],"ecosystems":["pypi"],"tags":["ai-agents","ai-tooling","cwe-22","langgraph","python","self-hosted"],"not_affected_if":["langgraph-platform","no-v3-streaming","trusted-identifiers"],"how_to_check":"- Run `pip show langgraph-sdk` and check whether the version is `0.4.0` through `0.4.5`\n- Run `pip show langgraph` and check whether the version is `1.2.3` through `1.2.13` with a vulnerable langgraph-sdk\n- Check whether application code passes user-controlled text as thread_id or assistant_id into streaming calls","fix":"- Upgrade `langgraph-sdk` to `0.4.6` or later\n- Upgrade `langgraph` to `1.2.14` or later if you use RemoteGraph, which requires `langgraph-sdk>=0.4.6`","status":"open","published_at":"2026-10-28T21:05:47+00:00","first_seen_at":"2026-10-28T21:07:44+00:00","triaged_at":"2026-10-28T21:09:31+00:00","updated_at":"2026-10-28T21:09:31+00:00","category":"ai-tooling","confidence":0.8,"triage":{"at":"2026-10-28T21:09:31Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade `langgraph-sdk` to `0.4.6` or later\n- Upgrade `langgraph` to `1.2.14` or later if you use RemoteGraph, which requires `langgraph-sdk>=0.4.6`","reach":"network","title":"LangGraph SDK: unencoded thread IDs let attackers redirect authenticated GET requests","impact":"low","summary":"The LangGraph Python SDK v3 streaming client puts caller-supplied thread_id and assistant_id values into request paths without encoding them, so relative path segments can redirect an authenticated GET to another readable path on the same server. An attacker who controls those identifiers can read another response on the configured server, and can control the query string through thread_id, but cannot write.","category":"ai-tooling","nicknames":[],"who_cares":["python","langgraph","ai-agents","self-hosted"],"confidence":0.8,"needs_auth":"yes","worst_case":"Attacker reads another readable path on the configured server","analyst_note":"","how_to_check":"- Run `pip show langgraph-sdk` and check whether the version is `0.4.0` through `0.4.5`\n- Run `pip show langgraph` and check whether the version is `1.2.3` through `1.2.13` with a vulnerable langgraph-sdk\n- Check whether application code passes user-controlled text as thread_id or assistant_id into streaming calls","needs_analyst":false,"not_affected_if":["langgraph-platform","trusted-identifiers","no-v3-streaming"],"who_is_affected":"Applications using the LangGraph Python SDK v3 streaming client that pass attacker-controlled text as a streaming thread_id or assistant_id are exposed, along with RemoteGraph v3 streaming users on affected SDK versions. The LangGraph Platform is not exposed. Teams that only use trusted, server-generated identifiers, or that do not use v3 streaming, can skip it.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"unknown"},"cost_usd":0.000753,"input_tokens":4024,"output_tokens":702,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-118667':16A,24A '-2026':15A,23A '-22':36B '/store/items':323C '0.3':222C '0.4.0':208C '0.4.5':210C '0.4.6':363C,408C '1.2.14':400C '1.2.3':231C '3fx2':19A 'affect':159C,212C,236C,259C,266C,333C 'agent':31B 'ai':30B,33B 'ai-ag':29B 'ai-tool':32B 'also':235C,314C,395C 'anoth':75B,90B,150C,290C 'applic':264C,307C 'assist':56B,123C,281C,326C,369C 'asynchron':136C,388C 'attack':83B,272C,287C,312C 'attacker-control':271C 'authent':11A,72B,146C,202C 'build':166C 'call':137C 'caller':51B,118C 'caller-suppli':50B,117C 'cannot':106B 'caus':298C 'client':48B,115C,200C 'collaps':190C 'config':248C 'configur':94B,155C,249C,285C,295C 'contain':192C 'control':85B,98B,273C,315C,328C 'cqw9':20A 'cve':14A,22A 'cwe':35B 'depend':256C 'detail':157C 'dispatch':196C 'encod':63B,130C,368C 'exampl':320C 'exist':181C 'expos':352C 'fetch':163C,378C 'fix':367C 'four':133C 'get':12A,73B,147C,160C,336C,372C 'ghsa':18A 'ghsa-3fx2-cqw9-xr3c':17A 'header':203C 'helper':185C 'host':41B 'http':186C 'id':54B,57B,104B,121C,124C,251C,279C,282C,310C,327C,370C,376C 'identifi':3A,87B,171C,176C 'impact':262C 'implement':165C 'interpol':116C 'issu':340C,355C 'key':325C 'langgraph':1A,5A,26A,28A,37B,43B,110C,205C,230C,243C,348C,359C,397C,406C 'langgraph-sdk':25A,204C,242C,358C,405C 'later':233C,365C,402C 'line':225C 'may':288C 'modul':216C,390C 'namespac':324C 'normal':188C 'oper':337C 'param':184C,383C 'pass':174C,247C,270C 'path':61B,67B,77B,128C,140C,151C,168C,183C,187C,292C,331C,382C 'permit':258C 'platform':349C 'present':219C 'primit':346C 'provid':343C 'put':49B 'python':38B,44B,111C 'queri':100B,317C 'quot':182C,381C 'rang':257C 'rather':172C 'raw':170C 'read':89B 'readabl':76B,291C 'redirect':10A,70B,144C 'relat':66B,139C,193C 'releas':224C 'remedi':356C 'remotegraph':226C,394C 'request':13A,60B,127C,148C,167C,334C 'requir':404C 'respons':91B,304C 'retain':198C 'return':302C 'sdk':6A,27A,45B,112C,179C,206C,244C,260C,300C,360C,407C 'segment':68B,141C,194C 'select':289C 'self':40B 'self-host':39B 'server':81B,95B,156C,296C 'site':138C 'state':164C,379C 'stream':8A,47B,114C,215C,228C,277C,389C 'string':101B,318C 'summari':108C 'suppli':52B,119C 'synchron':134C,386C 'target':322C 'text':274C 'therefor':143C 'thread':53B,103B,120C,250C,278C,309C,375C 'threads.stream':253C 'tool':34B 'tree':161C,373C 'unencod':2A 'upgrad':357C,396C 'use':238C,393C 'v3':7A,46B,113C,214C,227C 'valu':58B,125C,191C 'version':207C,245C,261C,362C,399C 'vulner':241C 'without':62B,129C 'write':107B,345C 'x':223C 'xr3c':21A","nicknames":[],"mitigations":[],"who_affected":"Applications using the LangGraph Python SDK v3 streaming client that pass attacker-controlled text as a streaming thread_id or assistant_id are exposed, along with RemoteGraph v3 streaming users on affected SDK versions. The LangGraph Platform is not exposed. Teams that only use trusted, server-generated identifiers, or that do not use v3 streaming, can skip it.","tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-28T21:05:47+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N","cvss_by":"GitHub","poc_count":0,"sources":[{"source":"ghsa","external_id":"GHSA-3fx2-cqw9-xr3c","url":"https://github.com/advisories/GHSA-3fx2-cqw9-xr3c","severity":"medium","published_at":"2026-10-28T21:05:47+00:00","modified_at":"2026-10-28T21:05:48+00:00","first_seen_at":"2026-10-28T21:07:44+00:00","fetched_at":"2026-10-28T21:07:44+00:00","note":null},{"source":"nvd","external_id":"CVE-2026-118667","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-118667","severity":null,"published_at":"2026-10-28T21:16:57+00:00","modified_at":"2026-10-28T21:16:57+00:00","first_seen_at":"2026-10-28T21:35:45+00:00","fetched_at":"2026-10-28T21:35:45+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}