CVE-2011-0420

MEDIUMCVSS v2 · 5.05.0—
EchelonGraph scoreLOW confidence

This CVE was only ever scored under CVSS v2.0. NVD CVSS v2.0 base 5.0 — v2 rates that MEDIUM (v2 bands: LOW 0.0–3.9 / MEDIUM 4.0–6.9 / HIGH 7.0–10.0; v2 has no CRITICAL band). Vector AV:N/AC:L/Au:N/C:N/I:N/A:P. CVSS v2 is an older, coarser metric than v3.1/v4.0 (no Scope, no User Interaction, no Attack Requirements), so it is not directly comparable to a v3 or v4 score. NVD has never re-scored this record under v3. EPSS predicts 14.4% exploitation probability in the next 30 days, which is reflected in EG Risk but does not lift the v2 base. Confidence: LOW.

Sources: epss, nvd_v2
Weaponized
5.0EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 14%CVSS v2: 5.0Exploit: Exploit-DB (verified) · epss top5pct · public exploitExposed: 0

A fix is available — apply it.

The grapheme_extract function in the Internationalization extension (Intl) for ICU for PHP 5.3.5 allows context-dependent attackers to cause a denial of service (crash) via an invalid size argument, which triggers a NULL pointer dereference.

CVSS v2.0 (legacy)
5.0MEDIUMNVD never assigned a CVSS v3 rating to this CVE
EG Score
5.0(low)
EG Risk
53(Track)
EG Risk 53/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity50% × 45%
Exploitation65% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
14%
EPSS %ILE
96%
KEV
Not listed

Published

February 19, 2011

Last Modified

April 29, 2026

References (24)

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulibapache2-mod-php5 (5.3.5-1ubuntu7.1) @ natty2026-05-29ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(2 across 2 ecosystems)
Debian:5.0(1)
PackageVulnerable rangeFixed inDependents
php55.2.6.dfsg.1-1+lenny10 ... 5.2.6.dfsg.1-1+lenny9 (8 versions)5.2.6.dfsg.1-1+lenny12—
Debian:6.0(1)
PackageVulnerable rangeFixed inDependents
php55.3.3-7, 5.3.3-7+squeeze1, 5.3.3-7+squeeze25.3.3-7+squeeze3—

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 1× in last 7d / 11× 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.

Showing the most recent 100 of 102 total refreshes for this CVE.

  1. 2026-08-25 13:43 UTCEPSS rescore
  2. 2026-08-19 16:58 UTCEPSS rescore
  3. 2026-08-18 13:42 UTCEPSS rescore
  4. 2026-08-15 01:25 UTCEPSS rescore
  5. 2026-08-09 13:41 UTCEPSS rescore
  6. 2026-08-08 16:31 UTCEPSS rescore
  7. 2026-08-06 13:41 UTCEPSS rescore
  8. 2026-08-05 19:12 UTCEPSS rescore
  9. 2026-08-04 15:04 UTCEPSS rescore
  10. 2026-08-01 04:10 UTCEPSS rescore
  11. 2026-07-30 01:26 UTCEPSS rescore
  12. 2026-07-26 13:42 UTCEG score recompute▲ 5.00
  13. 2026-07-23 14:14 UTCEPSS rescore
  14. 2026-07-23 01:04 UTCEG score recompute
  15. 2026-07-23 00:40 UTCEG score recompute
  16. 2026-07-23 00:08 UTCEG score recompute
  17. 2026-07-22 21:46 UTCEG score recompute
  18. 2026-07-22 14:03 UTCEPSS rescore
  19. 2026-07-21 15:21 UTCEPSS rescore
  20. 2026-07-20 17:03 UTCEPSS rescore
  21. 2026-07-20 17:03 UTCEPSS rescore
  22. 2026-07-19 02:25 UTCEPSS rescore
  23. 2026-07-19 02:25 UTCEPSS rescore
  24. 2026-07-18 10:00 UTCEPSS rescore
  25. 2026-07-16 16:58 UTCEPSS rescore
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  1. 2026-07-15 16:54 UTCEPSS rescore
  2. 2026-07-15 16:54 UTCEPSS rescore
  3. 2026-07-13 22:25 UTCEPSS rescore
  4. 2026-07-13 06:08 UTCEPSS rescore
  5. 2026-07-11 08:22 UTCEPSS rescore
  6. 2026-07-11 08:22 UTCEPSS rescore
  7. 2026-07-08 15:10 UTCEPSS rescore
  8. 2026-07-08 15:10 UTCEPSS rescore
  9. 2026-07-05 02:26 UTCEPSS rescore
  10. 2026-07-04 06:27 UTCEPSS rescore
  11. 2026-07-02 14:01 UTCEPSS rescore
  12. 2026-07-01 15:02 UTCEPSS rescore
  13. 2026-07-01 15:02 UTCEPSS rescore
  14. 2026-06-29 14:02 UTCEPSS rescore
  15. 2026-06-28 14:03 UTCEPSS rescore
  16. 2026-06-28 04:53 UTCEPSS rescore
  17. 2026-06-28 04:52 UTCEPSS rescore
  18. 2026-06-27 03:05 UTCEPSS rescore
  19. 2026-06-27 03:05 UTCEPSS rescore
  20. 2026-06-25 13:46 UTCEPSS rescore
  21. 2026-06-24 14:02 UTCEPSS rescore
  22. 2026-06-24 14:02 UTCEPSS rescore
  23. 2026-06-23 21:30 UTCEPSS rescore
  24. 2026-06-23 21:30 UTCEPSS rescore
  25. 2026-06-21 01:56 UTCEPSS rescore
  26. 2026-06-21 01:56 UTCEPSS rescore
  27. 2026-06-18 17:49 UTCEPSS rescore
  28. 2026-06-18 17:49 UTCEPSS rescore
  29. 2026-06-17 17:49 UTCEPSS rescore
  30. 2026-06-17 17:49 UTCEPSS rescore
  31. 2026-06-17 17:49 UTCEPSS rescore
  32. 2026-06-16 17:49 UTCEPSS rescore
  33. 2026-06-15 17:44 UTCEPSS rescore
  34. 2026-06-14 23:14 UTCEPSS rescore
  35. 2026-06-14 23:14 UTCEPSS rescore
  36. 2026-06-13 22:57 UTCEPSS rescore
  37. 2026-06-13 22:57 UTCEPSS rescore
  38. 2026-06-12 23:08 UTCEPSS rescore
  39. 2026-06-11 13:56 UTCEPSS rescore
  40. 2026-06-10 22:14 UTCEPSS rescore
  41. 2026-06-10 13:17 UTCEPSS rescore
  42. 2026-06-07 15:22 UTCEPSS rescore
  43. 2026-06-07 15:22 UTCEPSS rescore
  44. 2026-06-06 13:45 UTCEPSS rescore
  45. 2026-06-06 13:44 UTCEPSS rescore
  46. 2026-06-05 22:44 UTCEPSS rescore
  47. 2026-06-04 13:09 UTCEPSS rescore
  48. 2026-06-04 13:09 UTCEPSS rescore
  49. 2026-06-02 20:10 UTCEPSS rescore
  50. 2026-06-02 20:10 UTCEPSS rescore
  51. 2026-06-01 13:49 UTCEPSS rescore
  52. 2026-06-01 13:49 UTCEPSS rescore
  53. 2026-05-31 22:28 UTCEPSS rescore
  54. 2026-05-31 22:28 UTCEPSS rescore
  55. 2026-05-31 00:14 UTCEPSS rescore
  56. 2026-05-31 00:14 UTCEPSS rescore
  57. 2026-05-29 13:41 UTCEPSS rescore
  58. 2026-05-29 13:40 UTCEPSS rescore
  59. 2026-05-29 08:46 UTCEG score recompute
  60. 2026-05-29 08:46 UTCVendor advisory
  61. 2026-05-29 08:45 UTCGHSA enrichment
  62. 2026-05-28 13:42 UTCEPSS rescore
  63. 2026-05-28 13:42 UTCEPSS rescore
  64. 2026-05-28 13:42 UTCEPSS rescore
  65. 2026-05-27 13:38 UTCEPSS rescore
  66. 2026-05-27 13:38 UTCEPSS rescore
  67. 2026-05-26 13:41 UTCEPSS rescore
  68. 2026-05-26 13:41 UTCEPSS rescore
  69. 2026-05-24 16:43 UTCEPSS rescore
  70. 2026-05-20 22:37 UTCEPSS rescore
  71. 2026-05-20 22:37 UTCEPSS rescore
  72. 2026-05-20 22:37 UTCEPSS rescore
  73. 2026-05-20 11:21 UTCEPSS rescore
  74. 2026-05-20 11:21 UTCEPSS rescore
  75. 2026-05-20 11:21 UTCEPSS rescore

Publicly available exploits

(2 references)

Working exploit code is in the public domain (2 Exploit-DB entries). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Exploit-DBEDB-16182✓ verified
    First seen Feb 17, 2011

    PHP 5.3.5 - 'grapheme_extract()' Null Pointer Dereference

    Open source ↗
  • Exploit-DBEDB-35354✓ verified
    First seen Feb 17, 2011

    PHP 5.3.5 - 'grapheme_extract()' Null Pointer Dereference Denial of Service

    Open source ↗

Frequently asked(4)

What is CVE-2011-0420?
CVE-2011-0420 is a medium vulnerability published on February 19, 2011. The grapheme_extract function in the Internationalization extension (Intl) for ICU for PHP 5.3.5 allows context-dependent attackers to cause a denial of service (crash) via an invalid size argument, which triggers a NULL pointer dereference.
When was CVE-2011-0420 disclosed?
CVE-2011-0420 was first published in the National Vulnerability Database on February 19, 2011, with the most recent update on April 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2011-0420 actively exploited?
CVE-2011-0420 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 14% probability of exploitation in the next 30 days, which ranks it in the top 3.6% of all scored CVEs.
How do I remediate CVE-2011-0420?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2011-0420, 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.

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