# CVE-2026-126569: Mbin 1.2.1 before 1.11.1 Stored XSS via Markdown Image Nested in Link

Status: published. Published: 2026-11-11. Updated: 2026-11-11.

Mbin 1.2.1 before 1.11.1 contains a stored cross-site scripting vulnerability in EmbedElement::buildDestructed() that renders nested Markdown image alt text and URL without HTML escaping. Authenticated users can embed HTML in the alt text of an image inside a link in entries, comments, posts, messages, or bios to run script in viewers' browsers.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/MbinOrg/mbin/commit/736fd39fe9cd59f5d51636d25e1857d88ddbd0bd

## Affected products and versions

- MbinOrg / mbin (MbinOrg/mbin): ≥ 1.2.1; < 1.11.1 (affected, semver); 1.11.1 (unaffected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 5.1 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 5.4 (medium); CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-79

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/MbinOrg/mbin/security/advisories/GHSA-g3r9-j6w4-2257 (CNA: VulnCheck; vendor-advisory)

- https://github.com/MbinOrg/mbin/commit/736fd39fe9cd59f5d51636d25e1857d88ddbd0bd (CNA: VulnCheck; patch)

- https://github.com/MbinOrg/mbin/releases/tag/v1.11.1 (CNA: VulnCheck; release-notes)

- https://github.com/MbinOrg/mbin/blob/v1.11.0/src/Markdown/CommonMark/EmbedElement.php#L57-L67 (CNA: VulnCheck; technical-description)

- https://www.vulncheck.com/advisories/mbin-1.2.1-before-1.11.1-stored-xss-via-markdown-image-nested-in-link (CNA: VulnCheck; third-party-advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-126569; retrieved 2026-11-11; source updated 2026-11-11

Revision: e869065d86028ff24cc318d405dd335bd198c518dd3365a9ed4a70b3ea5cc597

Canonical: https://y2.dev/cve/CVE-2026-126569

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.