CVE-2021-29460

HIGHNVD 7.67.6—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.6 under NVD CVSS v3. EPSS exploit probability: 1.1%, top 22% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Elevated
7.6
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 3%CVSS: 7.6Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Kirby is an open source CMS. An editor with write access to the Kirby Panel can upload an SVG file that contains harmful content like ` tags. The direct link to that file can be sent to other users or visitors of the site. If the victim opens that link in a browser where they are logged in to Kirby, the script will run and can for example trigger requests to Kirby's API with the permissions of the victim. This vulnerability is critical if you might have potential attackers in your group of authenticated Panel users, as they can escalate their privileges if they get access to the Panel session of an admin user. Depending on your site, other JavaScript-powered attacks are possible. Visitors without Panel access can only use this attack vector if your site allows SVG file uploads in frontend forms and you don't already sanitize uploaded SVG files. The problem has been patched in Kirby 3.5.4. Please update to this or a later version to fix the vulnerability. Frontend upload forms need to be patched separately depending on how they store the uploaded file(s). If you use File::create()`, you are protected by updating to 3.5.4+. As a work around you can disable the upload of SVG files in your file blueprints.

CVSS v3
7.6
EG Score
7.6(medium)
EPSS
86.5%
KEV
Not listed

Published

April 27, 2021

Last Modified

November 21, 2024

References (6)

Affected Packages

(1 across 1 ecosystem)
Packagist(1)
PackageVulnerable rangeFixed inDependents
getkirby/cms3.0.0 ... 3.5.3.1 (76 versions)3.5.4—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 10× in last 7d / 44× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-11 08:25 UTCEPSS rescore
  2. 2026-07-11 08:25 UTCEPSS rescore
  3. 2026-07-09 19:07 UTCEPSS rescore
  4. 2026-07-08 15:12 UTCEPSS rescore
  5. 2026-07-07 13:43 UTCEPSS rescore
  6. 2026-07-06 16:25 UTCEPSS rescore
  7. 2026-07-06 16:25 UTCEPSS rescore
  8. 2026-07-06 02:21 UTCEPSS rescore
  9. 2026-07-06 02:21 UTCEPSS rescore
  10. 2026-07-05 02:28 UTCEPSS rescore
  11. 2026-07-04 06:29 UTCEPSS rescore
  12. 2026-07-04 06:29 UTCEPSS rescore
  13. 2026-07-02 16:57 UTCEPSS rescore
  14. 2026-07-01 15:03 UTCEPSS rescore
  15. 2026-07-01 04:18 UTCOSV refresh
  16. 2026-06-30 23:20 UTCEPSS rescore
  17. 2026-06-30 23:20 UTCEPSS rescore
  18. 2026-06-29 14:04 UTCEPSS rescore
  19. 2026-06-28 04:54 UTCEPSS rescore
  20. 2026-06-28 04:54 UTCEPSS rescore
  21. 2026-06-27 03:06 UTCEPSS rescore
  22. 2026-06-27 03:06 UTCEPSS rescore
  23. 2026-06-25 13:48 UTCEPSS rescore
  24. 2026-06-25 13:48 UTCEPSS rescore
  25. 2026-06-24 14:03 UTCEPSS rescore
Show 51 more
  1. 2026-06-24 14:03 UTCEPSS rescore
  2. 2026-06-22 14:24 UTCEPSS rescore
  3. 2026-06-22 14:24 UTCEPSS rescore
  4. 2026-06-21 14:55 UTCEPSS rescore
  5. 2026-06-21 14:54 UTCEPSS rescore
  6. 2026-06-21 01:58 UTCEPSS rescore
  7. 2026-06-21 01:58 UTCEPSS rescore
  8. 2026-06-19 19:24 UTCEPSS rescore
  9. 2026-06-19 19:24 UTCEPSS rescore
  10. 2026-06-18 17:51 UTCEPSS rescore
  11. 2026-06-18 17:51 UTCEPSS rescore
  12. 2026-06-17 17:51 UTCEPSS rescore
  13. 2026-06-16 17:51 UTCEPSS rescore
  14. 2026-06-15 17:46 UTCEPSS rescore
  15. 2026-06-14 23:15 UTCEPSS rescore
  16. 2026-06-13 22:58 UTCEPSS rescore
  17. 2026-06-13 22:58 UTCEPSS rescore
  18. 2026-06-13 07:13 UTCOSV refresh
  19. 2026-06-12 23:10 UTCEPSS rescore
  20. 2026-06-11 13:58 UTCEPSS rescore
  21. 2026-06-10 22:16 UTCEPSS rescore
  22. 2026-06-10 13:20 UTCEPSS rescore
  23. 2026-06-08 14:15 UTCEPSS rescore
  24. 2026-06-07 15:23 UTCEPSS rescore
  25. 2026-06-07 15:23 UTCEPSS rescore
  26. 2026-06-06 13:46 UTCEPSS rescore
  27. 2026-06-06 13:46 UTCEPSS rescore
  28. 2026-06-06 13:46 UTCEPSS rescore
  29. 2026-06-05 22:45 UTCEPSS rescore
  30. 2026-06-05 22:45 UTCEPSS rescore
  31. 2026-06-05 06:09 UTCEPSS rescore
  32. 2026-06-05 06:09 UTCEPSS rescore
  33. 2026-06-04 13:10 UTCEPSS rescore
  34. 2026-06-04 13:10 UTCEPSS rescore
  35. 2026-06-02 20:11 UTCEPSS rescore
  36. 2026-06-02 20:11 UTCEPSS rescore
  37. 2026-06-02 20:11 UTCEPSS rescore
  38. 2026-06-01 13:50 UTCEPSS rescore
  39. 2026-06-01 13:50 UTCEPSS rescore
  40. 2026-05-31 22:29 UTCEPSS rescore
  41. 2026-05-31 22:29 UTCEPSS rescore
  42. 2026-05-31 00:15 UTCEPSS rescore
  43. 2026-05-29 13:42 UTCEPSS rescore
  44. 2026-05-28 13:43 UTCEPSS rescore
  45. 2026-05-28 13:43 UTCEPSS rescore
  46. 2026-05-27 13:39 UTCEPSS rescore
  47. 2026-05-27 13:39 UTCEPSS rescore
  48. 2026-05-26 17:23 UTCEG score recompute
  49. 2026-05-26 13:42 UTCEPSS rescore
  50. 2026-05-26 07:17 UTCEPSS rescore
  51. 2026-05-26 07:17 UTCEPSS rescore

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Exploit-DBEDB-49808
    First seen Apr 28, 2021

    Kirby CMS 3.5.3.1 - 'file' Cross-Site Scripting (XSS)

    Open source ↗

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2021-29460?
CVE-2021-29460 is a high vulnerability published on April 27, 2021. Kirby is an open source CMS. An editor with write access to the Kirby Panel can upload an SVG file that contains harmful content like <script> tags. The direct link to that file can be sent to other users or visitors of the site. If the victim opens that link in a browser where they are logged in…
When was CVE-2021-29460 disclosed?
CVE-2021-29460 was first published in the National Vulnerability Database on April 27, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-29460 actively exploited?
CVE-2021-29460 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 86.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-29460?
CVE-2021-29460 has a CVSS v3 base score of 7.6 (NVD).
How do I remediate CVE-2021-29460?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-29460, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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