CVE-2009-3421

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory published 2022-05-02. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Weaponized
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 5%CVSS: 9.8Exploit: NoneExposed: 0

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

login.php in Zenas PaoBacheca Guestbook 2.1, when register_globals is enabled, allows remote attackers to bypass authentication and gain administrative access by setting the login_ok parameter to 1.

CVSS v3
9.8
EG Score
9.8(medium)
EPSS
91.2%
KEV
Not listed

Published

September 25, 2009

Last Modified

April 23, 2026

Advisory Details (3)

Auto-updated May 11, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic

IBM X-Force Exchange

https://exchange.xforce.ibmcloud.com/vulnerabilities/52100
generic🟡 PoC Available

PaoBacheca Guestbook 2.1 - 'login_ok' Authentication Bypass - PHP webapps Exploit

http://www.exploit-db.com/exploits/9293
generic

About Secunia Research | Flexera

http://secunia.com/advisories/36023

Data Freshness Timeline

(refreshed 7× in last 7d / 38× 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. 2026-07-06 16:23 UTCEPSS rescore
  2. 2026-07-06 02:19 UTCEPSS rescore
  3. 2026-07-06 02:19 UTCEPSS rescore
  4. 2026-07-05 02:26 UTCEPSS rescore
  5. 2026-07-05 02:26 UTCEPSS rescore
  6. 2026-07-04 06:27 UTCEPSS rescore
  7. 2026-07-01 15:02 UTCEPSS rescore
  8. 2026-06-30 23:19 UTCEPSS rescore
  9. 2026-06-28 14:03 UTCEPSS rescore
  10. 2026-06-28 04:52 UTCEPSS rescore
  11. 2026-06-28 04:52 UTCEPSS rescore
  12. 2026-06-27 03:05 UTCEPSS rescore
  13. 2026-06-25 13:46 UTCEPSS rescore
  14. 2026-06-25 13:46 UTCEPSS rescore
  15. 2026-06-24 14:02 UTCEPSS rescore
  16. 2026-06-24 14:02 UTCEPSS rescore
  17. 2026-06-23 21:29 UTCEPSS rescore
  18. 2026-06-23 21:29 UTCEPSS rescore
  19. 2026-06-21 14:53 UTCEPSS rescore
  20. 2026-06-21 01:56 UTCEPSS rescore
  21. 2026-06-21 01:56 UTCEPSS rescore
  22. 2026-06-19 19:22 UTCEPSS rescore
  23. 2026-06-19 19:22 UTCEPSS rescore
  24. 2026-06-18 17:49 UTCEPSS rescore
  25. 2026-06-18 17:49 UTCEPSS rescore
Show 65 more
  1. 2026-06-17 17:49 UTCEPSS rescore
  2. 2026-06-17 17:49 UTCEPSS rescore
  3. 2026-06-16 17:49 UTCEPSS rescore
  4. 2026-06-16 17:49 UTCEPSS rescore
  5. 2026-06-15 17:44 UTCEPSS rescore
  6. 2026-06-14 23:14 UTCEPSS rescore
  7. 2026-06-14 23:14 UTCEPSS rescore
  8. 2026-06-13 22:57 UTCEPSS rescore
  9. 2026-06-12 23:08 UTCEPSS rescore
  10. 2026-06-12 23:08 UTCEPSS rescore
  11. 2026-06-10 22:14 UTCEPSS rescore
  12. 2026-06-10 13:17 UTCEPSS rescore
  13. 2026-06-08 14:13 UTCEPSS rescore
  14. 2026-06-07 15:22 UTCEPSS rescore
  15. 2026-06-07 15:22 UTCEPSS rescore
  16. 2026-06-06 13:44 UTCEPSS rescore
  17. 2026-06-06 13:44 UTCEPSS rescore
  18. 2026-06-06 13:44 UTCEPSS rescore
  19. 2026-06-05 22:44 UTCEPSS rescore
  20. 2026-06-05 22:44 UTCEPSS rescore
  21. 2026-06-05 06:07 UTCEPSS rescore
  22. 2026-06-04 13:09 UTCEPSS rescore
  23. 2026-06-04 13:09 UTCEPSS rescore
  24. 2026-06-02 20:10 UTCEPSS rescore
  25. 2026-06-02 20:10 UTCEPSS rescore
  26. 2026-06-01 13:49 UTCEPSS rescore
  27. 2026-06-01 13:49 UTCEPSS rescore
  28. 2026-05-31 22:28 UTCEPSS rescore
  29. 2026-05-31 22:28 UTCEPSS rescore
  30. 2026-05-31 00:13 UTCEPSS rescore
  31. 2026-05-31 00:13 UTCEPSS rescore
  32. 2026-05-29 13:40 UTCEPSS rescore
  33. 2026-05-28 13:42 UTCEPSS rescore
  34. 2026-05-28 13:42 UTCEPSS rescore
  35. 2026-05-28 13:42 UTCEPSS rescore
  36. 2026-05-27 13:38 UTCEPSS rescore
  37. 2026-05-27 13:38 UTCEPSS rescore
  38. 2026-05-26 13:41 UTCEPSS rescore
  39. 2026-05-26 13:41 UTCEPSS rescore
  40. 2026-05-24 16:43 UTCEPSS rescore
  41. 2026-05-22 21:15 UTCEPSS rescore
  42. 2026-05-22 21:15 UTCEPSS rescore
  43. 2026-05-20 22:37 UTCEPSS rescore
  44. 2026-05-20 22:37 UTCEPSS rescore
  45. 2026-05-20 11:21 UTCEPSS rescore
  46. 2026-05-20 11:20 UTCEPSS rescore
  47. 2026-05-20 11:02 UTCEG score recompute
  48. 2026-05-20 11:02 UTCGHSA enrichment
  49. 2026-05-20 06:51 UTCEG score recompute
  50. 2026-05-20 06:51 UTCGHSA enrichment
  51. 2026-05-20 02:44 UTCEG score recompute
  52. 2026-05-20 02:44 UTCGHSA enrichment
  53. 2026-05-19 22:44 UTCEG score recompute
  54. 2026-05-19 22:44 UTCGHSA enrichment
  55. 2026-05-19 18:43 UTCEG score recompute
  56. 2026-05-19 18:43 UTCGHSA enrichment
  57. 2026-05-19 14:33 UTCEG score recompute
  58. 2026-05-19 14:33 UTCGHSA enrichment
  59. 2026-05-19 09:45 UTCEG score recompute
  60. 2026-05-19 09:45 UTCGHSA enrichment
  61. 2026-05-19 05:41 UTCEG score recompute
  62. 2026-05-19 05:41 UTCGHSA enrichment
  63. 2026-05-19 01:42 UTCEG score recompute
  64. 2026-05-19 01:42 UTCGHSA enrichment
  65. 2026-05-18 21:29 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-9293✓ verified
    First seen Jul 28, 2009

    PaoBacheca Guestbook 2.1 - 'login_ok' Authentication Bypass

    Open source ↗

Frequently asked(5)

What is CVE-2009-3421?
CVE-2009-3421 is a critical vulnerability published on September 25, 2009. login.php in Zenas PaoBacheca Guestbook 2.1, when registerglobals is enabled, allows remote attackers to bypass authentication and gain administrative access by setting the loginok parameter to 1.
When was CVE-2009-3421 disclosed?
CVE-2009-3421 was first published in the National Vulnerability Database on September 25, 2009, with the most recent update on April 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2009-3421 actively exploited?
CVE-2009-3421 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 91.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2009-3421?
CVE-2009-3421 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2009-3421?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2009-3421, 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

Explore the affected products and dependency analysis for CVE-2009-3421

Explore →

Is Your Infrastructure Affected by CVE-2009-3421?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs