CVE-2008-5557

HIGHCVSS v2 · 10.010.0—
EchelonGraph scoreLOW confidence

This CVE was only ever scored under CVSS v2.0. NVD CVSS v2.0 base 10.0 — v2 rates that HIGH (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:C/I:C/A:C. 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 7.4% 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
10.0EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 7%CVSS v2: 10.0Exploit: None knownExposed: 0

A fix is available — apply it.

Heap-based buffer overflow in ext/mbstring/libmbfl/filters/mbfilter_htmlent.c in the mbstring extension in PHP 4.3.0 through 5.2.6 allows context-dependent attackers to execute arbitrary code via a crafted string containing an HTML entity, which is not properly handled during Unicode conversion, related to the (1) mb_convert_encoding, (2) mb_check_encoding, (3) mb_convert_variables, and (4) mb_parse_str functions.

CVSS v2.0 (legacy)
10.0HIGHNVD never assigned a CVSS v3 rating to this CVE
EG Score
10.0(low)
EG Risk
52(Track)
EG Risk 52/100SSVC: 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
Severity100% × 45%
Exploitation7% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
7%
EPSS %ILE
94%
KEV
Not listed

Published

December 23, 2008

Last Modified

April 23, 2026

References (58)

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulibapache2-mod-php5filter (5.2.6-2ubuntu4.1) @ intrepid2026-05-30ubuntu
redhatphp-0:5.1.6-23.2.el5_32009-04-06redhat
redhatphp-0:4.3.9-3.22.152009-04-06redhat

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:4.0(1)
PackageVulnerable rangeFixed inDependents
php55.2.0-10 ... 5.2.0-9 (17 versions)5.2.0+dfsg-8+etch15—
Debian:5.0(1)
PackageVulnerable rangeFixed inDependents
php55.2.6.dfsg.1-1+lenny25.2.6.dfsg.1-1+lenny2—

Weakness Classification(1)

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

All Vendor Advisories

(3)

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 0× in last 7d / 8× 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 103 total refreshes for this CVE.

  1. 2026-08-15 01:24 UTCEPSS rescore
  2. 2026-08-08 16:31 UTCEPSS rescore
  3. 2026-08-07 16:21 UTCEPSS rescore
  4. 2026-08-06 13:41 UTCEPSS rescore
  5. 2026-08-05 19:11 UTCEPSS rescore
  6. 2026-08-04 15:03 UTCEPSS rescore
  7. 2026-08-03 10:28 UTCEPSS rescore
  8. 2026-07-30 01:25 UTCEPSS rescore
  9. 2026-07-26 13:36 UTCEG score recompute▲ 10.00
  10. 2026-07-25 14:12 UTCEPSS rescore
  11. 2026-07-24 14:12 UTCEPSS rescore
  12. 2026-07-23 14:14 UTCEPSS rescore
  13. 2026-07-23 00:57 UTCEG score recompute
  14. 2026-07-23 00:35 UTCEG score recompute
  15. 2026-07-23 00:02 UTCEG score recompute
  16. 2026-07-22 21:41 UTCEG score recompute
  17. 2026-07-20 17:03 UTCEPSS rescore
  18. 2026-07-18 09:59 UTCEPSS rescore
  19. 2026-07-16 16:58 UTCEPSS rescore
  20. 2026-07-15 16:54 UTCEPSS rescore
  21. 2026-07-15 16:54 UTCEPSS rescore
  22. 2026-07-15 01:55 UTCEPSS rescore
  23. 2026-07-13 22:25 UTCEPSS rescore
  24. 2026-07-11 08:22 UTCEPSS rescore
  25. 2026-07-11 08:22 UTCEPSS rescore
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  1. 2026-07-09 19:04 UTCEPSS rescore
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  3. 2026-07-06 16:23 UTCEPSS rescore
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  5. 2026-07-06 02:19 UTCEPSS rescore
  6. 2026-07-05 02:26 UTCEPSS rescore
  7. 2026-07-05 02:26 UTCEPSS rescore
  8. 2026-07-04 06:27 UTCEPSS rescore
  9. 2026-07-02 14:00 UTCEPSS rescore
  10. 2026-07-01 15:02 UTCEPSS rescore
  11. 2026-07-01 15:02 UTCEPSS rescore
  12. 2026-06-30 23:19 UTCEPSS rescore
  13. 2026-06-29 14:02 UTCEPSS rescore
  14. 2026-06-29 14:02 UTCEPSS rescore
  15. 2026-06-28 14:03 UTCEPSS rescore
  16. 2026-06-28 04:52 UTCEPSS rescore
  17. 2026-06-27 03:04 UTCEPSS rescore
  18. 2026-06-25 13:46 UTCEPSS rescore
  19. 2026-06-25 13:46 UTCEPSS rescore
  20. 2026-06-24 14:02 UTCEPSS rescore
  21. 2026-06-24 14:02 UTCEPSS rescore
  22. 2026-06-23 21:29 UTCEPSS rescore
  23. 2026-06-23 21:29 UTCEPSS rescore
  24. 2026-06-22 14:22 UTCEPSS rescore
  25. 2026-06-22 14:22 UTCEPSS rescore
  26. 2026-06-21 01:56 UTCEPSS rescore
  27. 2026-06-21 01:56 UTCEPSS rescore
  28. 2026-06-19 19:22 UTCEPSS rescore
  29. 2026-06-19 19:22 UTCEPSS rescore
  30. 2026-06-18 17:49 UTCEPSS rescore
  31. 2026-06-18 17:49 UTCEPSS rescore
  32. 2026-06-17 17:49 UTCEPSS rescore
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  34. 2026-06-16 17:49 UTCEPSS rescore
  35. 2026-06-16 17:49 UTCEPSS rescore
  36. 2026-06-15 17:44 UTCEPSS rescore
  37. 2026-06-14 23:13 UTCEPSS rescore
  38. 2026-06-13 22:57 UTCEPSS rescore
  39. 2026-06-12 23:08 UTCEPSS rescore
  40. 2026-06-12 23:08 UTCEPSS rescore
  41. 2026-06-11 13:56 UTCEPSS rescore
  42. 2026-06-10 22:14 UTCEPSS rescore
  43. 2026-06-10 13:17 UTCEPSS rescore
  44. 2026-06-08 14:13 UTCEPSS rescore
  45. 2026-06-07 15:22 UTCEPSS rescore
  46. 2026-06-06 13:44 UTCEPSS rescore
  47. 2026-06-06 13:44 UTCEPSS rescore
  48. 2026-06-05 22:44 UTCEPSS rescore
  49. 2026-06-05 22:44 UTCEPSS rescore
  50. 2026-06-05 06:07 UTCEPSS rescore
  51. 2026-06-04 13:09 UTCEPSS rescore
  52. 2026-06-04 13:09 UTCEPSS rescore
  53. 2026-06-02 20:10 UTCEPSS rescore
  54. 2026-06-02 20:10 UTCEPSS rescore
  55. 2026-06-01 13:49 UTCEPSS rescore
  56. 2026-06-01 13:49 UTCEPSS rescore
  57. 2026-06-01 13:49 UTCEPSS rescore
  58. 2026-05-31 22:28 UTCEPSS rescore
  59. 2026-05-31 22:28 UTCEPSS rescore
  60. 2026-05-30 18:58 UTCEG score recompute
  61. 2026-05-30 18:58 UTCVendor advisory
  62. 2026-05-30 18:58 UTCGHSA enrichment
  63. 2026-05-29 13:40 UTCEPSS rescore
  64. 2026-05-28 13:42 UTCEPSS rescore
  65. 2026-05-28 13:42 UTCEPSS rescore
  66. 2026-05-28 13:42 UTCEPSS rescore
  67. 2026-05-27 13:38 UTCEPSS rescore
  68. 2026-05-27 13:37 UTCEPSS rescore
  69. 2026-05-26 13:41 UTCEPSS rescore
  70. 2026-05-26 13:41 UTCEPSS rescore
  71. 2026-05-24 16:43 UTCEPSS rescore
  72. 2026-05-22 21:15 UTCEPSS rescore
  73. 2026-05-22 21:15 UTCEPSS rescore
  74. 2026-05-20 22:37 UTCEPSS rescore
  75. 2026-05-20 22:36 UTCEPSS rescore

Frequently asked(4)

What is CVE-2008-5557?
CVE-2008-5557 is a high vulnerability published on December 23, 2008. Heap-based buffer overflow in ext/mbstring/libmbfl/filters/mbfilterhtmlent.c in the mbstring extension in PHP 4.3.0 through 5.2.6 allows context-dependent attackers to execute arbitrary code via a crafted string containing an HTML entity, which is not properly handled during Unicode conversion,…
When was CVE-2008-5557 disclosed?
CVE-2008-5557 was first published in the National Vulnerability Database on December 23, 2008, 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-2008-5557 actively exploited?
CVE-2008-5557 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 7% probability of exploitation in the next 30 days, which ranks it in the top 6.1% of all scored CVEs.
How do I remediate CVE-2008-5557?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2008-5557, 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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