# CVE-2026-57448: Blombooru: administrator image-proxy server-side request forgery

Status: published. Published: 2026-10-28. Updated: 2026-11-03.

Blombooru is a self-hosted personal booru for organizing and tagging private image collections. Prior to 1.40.0, the administrator-only `GET /proxy-image` endpoint, exposed as `/api/booru-import/proxy-image`, accepts a `url` query parameter and fetches it server-side without meaningful destination validation. `proxy_image()` in `backend/app/routes/booru_import.py` only checks whether the value starts with http, then uses `get_client_for_url` or `requests.get` and streams the response. Private, loopback and link-local addresses are not blocked, and automatically followed redirects can move a request from a trusted domain to an internal address. An authenticated administrator can enumerate internal services and access cloud instance metadata, potentially disclosing IAM credentials and crossing the application's intended cloud or network trust boundary. The reporter also observed a hanging recursive self-request. Administrator authentication remains a prerequisite; this is not an anonymous proxy. This issue is fixed in version 1.40.0.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- mrblomblo / blombooru: < 1.40.0 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 4.0: 6.2 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:N/VA:N/SC:H/SI:L/SA:N; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: 0.34% as of 2026-11-02; percentile 27.66%

- SSVC: exploitation poc; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-918

## Exploit evidence

- exploit: https://github.com/mrblomblo/blombooru/security/advisories/GHSA-5c5w-x8jp-fjqw (ADP: CISA-ADP)

## References

- https://github.com/mrblomblo/blombooru/security/advisories/GHSA-5c5w-x8jp-fjqw (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/mrblomblo/blombooru/commit/fad91894b421f64cc40d2db29d72cc7a8c94048d (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/mrblomblo/blombooru/releases/tag/v1.40.0 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/mrblomblo/blombooru/security/advisories/GHSA-5c5w-x8jp-fjqw (ADP: CISA-ADP; exploit)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-57448; retrieved 2026-11-03; source updated 2026-11-03

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-57448; retrieved 2026-11-03; source updated Not reported

Revision: b85ea76969894a7b0cec93b908fcb46d7989d41f9eecad0851e2869f0bbee808

Canonical: https://y2.dev/cve/CVE-2026-57448

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