CVE-2011-4858

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 80.3% 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 verdictPatch this weekExploitation is likely or a public exploit exists.
  • 57 internet-exposed hosts are running an affected version right now
  • High exploitation likelihood — EPSS 80%
  • Public exploit code is available (Metasploit, Exploit-DB (verified), epss top5pct, epss high, public exploit)
CISA-KEV: Not listedEPSS PROB: 80%CVSS v2: 5.0Exploit: Metasploit · Exploit-DB (verified) · epss top5pct · epss high · public exploitExposed: 57

A fix is available — apply it.

Apache Tomcat before 5.5.35, 6.x before 6.0.35, and 7.x before 7.0.23 computes hash values for form parameters without restricting the ability to trigger hash collisions predictably, which allows remote attackers to cause a denial of service (CPU consumption) by sending many crafted parameters.

Live · internet exposure

57 internet-exposed hosts are running an affected version of CVE-2011-4858 right now.

across 16 countries (China, United States, Germany, Singapore, Pakistan)top: tomcat
See the live KEV-Exposure radar →Found passively from public internet-scan data — aggregate, host-redacted.

EchelonGraph is the only CVE feed that fuses live vulnerability intelligence with its own live internet-exposure radar — so you see not just that a CVE is exploited, but how much of the internet is exposed to it right now.

CVSS v2.0 (legacy)
5.0MEDIUMNVD never assigned a CVSS v3 rating to this CVE
EG Score
5.0(low)
EG Risk
59(Track)
EG Risk 59/100SSVC: 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%
Exploitation80% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
80%
EPSS %ILE
100%
KEV
Not listed

Published

January 5, 2012

Last Modified

April 29, 2026

References (52)

Patch Availability(16)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulibtomcat6-java (6.0.28-10ubuntu2.3) @ natty2026-05-29ubuntu
redhattomcat5-0:5.5.33-28_patch_07.ep5.el62012-05-21redhat
redhattomcat6-0:6.0.32-24_patch_07.ep5.el62012-05-21redhat
redhatpatch2012-05-21redhat
redhatpatch2012-05-21redhat
redhattomcat5-0:5.5.23-0jpp.31.el5_82012-04-11redhat
redhattomcat6-0:6.0.24-36.el6_22012-04-11redhat
redhatpatch2012-03-20redhat
redhatpatch2012-02-22redhat
redhatpatch2012-02-02redhat
redhatpatch2012-02-01redhat
redhatjbossweb-0:2.1.12-3_patch_03.2.ep5.el62012-01-31redhat
redhatpatch2012-01-31redhat
redhatpatch2012-01-31redhat
redhatpatch2012-01-31redhat
redhatpatch2012-01-19redhat

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

(1 across 1 ecosystem)
Maven(1)
PackageVulnerable rangeFixed inDependents
org.apache.tomcat:tomcat—7.0.23—

All Vendor Advisories

(17)

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 9× in last 7d / 18× 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. 2026-07-26 13:44 UTCEG score recompute▲ 5.00
  2. 2026-07-25 14:12 UTCEPSS rescore
  3. 2026-07-23 01:06 UTCEG score recompute▼ 8.20
  4. 2026-07-23 00:09 UTCEG score recompute▲ 8.20
  5. 2026-07-22 21:48 UTCEG score recompute
  6. 2026-07-22 14:04 UTCEPSS rescore
  7. 2026-07-22 14:04 UTCEPSS rescore
  8. 2026-07-20 17:03 UTCEPSS rescore
  9. 2026-07-20 17:03 UTCEPSS rescore
  10. 2026-07-16 16:58 UTCEPSS rescore
  11. 2026-07-15 16:54 UTCEPSS rescore
  12. 2026-07-15 16:54 UTCEPSS rescore
  13. 2026-07-08 15:10 UTCEPSS rescore
  14. 2026-07-08 15:10 UTCEPSS rescore
  15. 2026-07-04 06:27 UTCEPSS rescore
  16. 2026-07-01 15:02 UTCEPSS rescore
  17. 2026-06-30 23:19 UTCEPSS rescore
  18. 2026-06-30 23:19 UTCEPSS rescore
  19. 2026-06-25 13:46 UTCEPSS rescore
  20. 2026-06-25 13:46 UTCEPSS rescore
  21. 2026-06-23 21:30 UTCEPSS rescore
  22. 2026-06-21 14:53 UTCEPSS rescore
  23. 2026-06-21 01:56 UTCEPSS rescore
  24. 2026-06-21 01:56 UTCEPSS rescore
  25. 2026-06-16 17:49 UTCEPSS rescore
Show 41 more
  1. 2026-06-16 17:49 UTCEPSS rescore
  2. 2026-06-15 17:44 UTCEPSS rescore
  3. 2026-06-14 23:14 UTCEPSS rescore
  4. 2026-06-14 23:14 UTCEPSS rescore
  5. 2026-06-13 22:57 UTCEPSS rescore
  6. 2026-06-12 23:08 UTCEPSS rescore
  7. 2026-06-11 13:56 UTCEPSS rescore
  8. 2026-06-10 22:14 UTCEPSS rescore
  9. 2026-06-10 13:18 UTCEPSS rescore
  10. 2026-06-08 14:14 UTCEPSS rescore
  11. 2026-06-08 14:14 UTCEPSS rescore
  12. 2026-06-07 15:22 UTCEPSS rescore
  13. 2026-06-07 15:22 UTCEPSS rescore
  14. 2026-06-06 13:45 UTCEPSS rescore
  15. 2026-06-06 13:45 UTCEPSS rescore
  16. 2026-06-05 22:44 UTCEPSS rescore
  17. 2026-06-05 22:44 UTCEPSS rescore
  18. 2026-06-05 06:08 UTCEPSS rescore
  19. 2026-06-05 06:08 UTCEPSS rescore
  20. 2026-06-02 20:10 UTCEPSS rescore
  21. 2026-06-02 20:10 UTCEPSS rescore
  22. 2026-06-01 13:49 UTCEPSS rescore
  23. 2026-05-31 00:14 UTCEPSS rescore
  24. 2026-05-31 00:14 UTCEPSS rescore
  25. 2026-05-29 13:41 UTCEPSS rescore
  26. 2026-05-29 05:50 UTCEG score recompute
  27. 2026-05-29 05:50 UTCVendor advisory
  28. 2026-05-28 13:42 UTCEPSS rescore
  29. 2026-05-28 13:42 UTCEPSS rescore
  30. 2026-05-26 07:16 UTCEPSS rescore
  31. 2026-05-26 07:16 UTCEPSS rescore
  32. 2026-05-26 07:16 UTCEPSS rescore
  33. 2026-05-24 16:43 UTCEPSS rescore
  34. 2026-05-22 21:15 UTCEPSS rescore
  35. 2026-05-22 21:15 UTCEPSS rescore
  36. 2026-05-22 21:15 UTCEPSS rescore
  37. 2026-05-20 11:21 UTCEPSS rescore
  38. 2026-05-20 11:21 UTCEPSS rescore
  39. 2026-05-20 11:21 UTCEPSS rescore
  40. 2026-05-18 21:29 UTCEPSS rescore
  41. 2026-05-18 21:29 UTCEPSS rescore

Publicly available exploits

(2 references)

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

  • Metasploitauxiliary/dos/http/hashcollision_dos✓ verified
    First seen Dec 28, 2011

    Hashtable Collisions

    Open source ↗
  • Exploit-DBEDB-2012✓ verified
    First seen Jul 15, 2006

    MyBulletinBoard (MyBB) 1.1.5 - 'CLIENT-IP' SQL Injection

    Open source ↗

Frequently asked(4)

What is CVE-2011-4858?
CVE-2011-4858 is a medium vulnerability published on January 5, 2012. Apache Tomcat before 5.5.35, 6.x before 6.0.35, and 7.x before 7.0.23 computes hash values for form parameters without restricting the ability to trigger hash collisions predictably, which allows remote attackers to cause a denial of service (CPU consumption) by sending many crafted parameters.
When was CVE-2011-4858 disclosed?
CVE-2011-4858 was first published in the National Vulnerability Database on January 5, 2012, 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-2011-4858 actively exploited?
CVE-2011-4858 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 80% probability of exploitation in the next 30 days, which ranks it in the top 0.4% of all scored CVEs.
How do I remediate CVE-2011-4858?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2011-4858, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2011-4858

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