# CVE-2026-126305: EspoCRM before 10.0.9 Stored XSS via Knowledge Base Article Attachments

Status: published. Published: 2026-11-13. Updated: 2026-11-13.

EspoCRM before 9.3.11 and 10.x before 10.0.9 contains a stored cross-site scripting vulnerability in Knowledge Base articles that lets users with Knowledge Base create or edit access attach a JavaScript file and add a crafted link to the article body. When an administrator clicks the link, the script runs in their session and can create an administrator account with attacker-chosen credentials.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- espocrm / espocrm: ≥ 10.0.0; < 10.0.9 (affected, semver); 10.0.9 (unaffected, semver). Source: CNA: VulnCheck
- espocrm / espocrm: ≥ 0; < 9.3.11 (affected, semver); 9.3.11 (unaffected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 8.5 (high); CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 7.3 (high); CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N; source: CNA: VulnCheck

- CVSS 4.0: 8.5 (high); CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 7.3 (high); CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N; source: NVD: disclosure@vulncheck.com

- 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/espocrm/espocrm/security/advisories/GHSA-j6q5-9jwj-9p8q (CNA: VulnCheck; vendor-advisory)

- https://www.vulncheck.com/advisories/espocrm-before-10.0.9-stored-xss-via-knowledge-base-article-attachments (CNA: VulnCheck; third-party-advisory)

- https://github.com/espocrm/espocrm/security/advisories/GHSA-j6q5-9jwj-9p8q (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/espocrm-before-10.0.9-stored-xss-via-knowledge-base-article-attachments (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-126305; retrieved 2026-11-13; source updated 2026-11-13

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-126305; retrieved 2026-11-13; source updated 2026-11-13

Revision: ead6faeb1bf8242680bbb6a002a7c2210ecab0767ecee764cee0dd2357833001

Canonical: https://y2.dev/cve/CVE-2026-126305

## 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.