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Vulnerability record · CVE-2020-21524 · published 30 September 2020

CVE-2020-21524: Halo xml external entity (xxe) vulnerability

Halo · Halo

There is a XML external entity (XXE) vulnerability in halo v1.1.3, The function of importing other blogs in the background(/api/admin/migrations/wordpress) needs to parse the xml file, but it is not used for security defense, This vulnerability can detect the intranet, read files, enable ddos attacks, etc. exp:https://github.com/halo-dev/halo/issues/423

9.1 CVSS 3.1 Critical EPSS 1.5% · top 26.6% CWE-611 · XML external entity (XXE)
9.1CVSS 3.1 base score, v2 6.4
1.5%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

There is a XML external entity (XXE) vulnerability in halo v1.1.3, The function of importing other blogs in the background(/api/admin/migrations/wordpress) needs to parse the xml file, but it is not used for security defense, This vulnerability can detect the intranet, read files, enable ddos attacks, etc. exp:https://github.com/halo-dev/halo/issues/423

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/halo-dev/halo/issues/423 ExploitIssue TrackingThird Party Advisory
https://github.com/halo-dev/halo/issues/423 ExploitIssue TrackingThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2022-32994Halo unrestricted file upload vulnerabilityHalo CMS v1.5.3 was discovered to contain an arbitrary file upload vulnerability via the component /api/admin/attachments/upload.EPSS 19%9.8CVE-2022-32995Halo server-side request forgery (ssrf) vulnerabilityHalo CMS v1.5.3 was discovered to contain a Server-Side Request Forgery (SSRF) via the template remote download function.EPSS 18%9.8CVE-2020-18980Halo vulnerabilityRemote Code Executon vulnerability in Halo 0.4.3 via the remoteAddr and themeName parameters.EPSS 1.5%9.8CVE-2020-21526Halo path traversal vulnerabilityAn Arbitrary file writing vulnerability in halo v1.1.3. In an interface to write files in the background, a directory traversal check is performed on…EPSS 1.9%9.8CVE-2020-21522Halo path traversal vulnerabilityAn issue was discovered in halo V1.1.3. A Zip Slip Directory Traversal Vulnerability in the backend,the attacker can overwrite some files, such as ft…EPSS 1.5%9.8CVE-2020-21523Halo injection vulnerabilityA Server-Side Freemarker template injection vulnerability in halo CMS v1.1.3 In the Edit Theme File function. The ftl file can be edited. This is the…EPSS 2.6%9.1CVE-2025-44594Halo server-side request forgery (ssrf) vulnerabilityhalo v2.20.17 and before is vulnerable to server-side request forgery (SSRF) in /apis/uc.api.storage.halo.run/v1alpha1/attachments/-/upload-from-url.EPSS 0.37%9.1CVE-2020-19038Halo missing authorization vulnerabilityFile Deletion vulnerability in Halo 0.4.3 via delBackup.EPSS 1.2%

Source: NIST National Vulnerability Database (record CVE-2020-21524), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.