CVE-2008-1891

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:P/I:N/A:N. 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 2.8% 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
5.0EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 3%CVSS v2: 5.0Exploit: None knownExposed: 0

A fix is available — apply it.

Directory traversal vulnerability in WEBrick in Ruby 1.8.4 and earlier, 1.8.5 before 1.8.5-p231, 1.8.6 before 1.8.6-p230, 1.8.7 before 1.8.7-p22, and 1.9.0 before 1.9.0-2, when using NTFS or FAT filesystems, allows remote attackers to read arbitrary CGI files via a trailing (1) + (plus), (2) %2b (encoded plus), (3) . (dot), (4) %2e (encoded dot), or (5) %20 (encoded space) character in the URI, possibly related to the WEBrick::HTTPServlet::FileHandler and WEBrick::HTTPServer.new functionality and the :DocumentRoot option.

CVSS v2.0 (legacy)
5.0MEDIUMNVD never assigned a CVSS v3 rating to this CVE
EG Score
5.0(low)
EG Risk
28(Track)
EG Risk 28/100SSVC: 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%
Exploitation3% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
3%
EPSS %ILE
85%
KEV
Not listed

Published

April 18, 2008

Last Modified

April 23, 2026

References (22)

Vendor Advisories for CVE-2008-1891(3)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatruby4-0-main-4.0.0-33.3.hum12026-04-17redhat
redhatruby3-3-main-3.3.10-23.1.hum12026-04-09redhat
redhatruby3-4-main-3.4.8-31.1.hum12026-04-09redhat

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.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 33× 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 13:35 UTCEG score recompute▲ 5.00
  2. 2026-07-25 14:12 UTCEPSS rescore
  3. 2026-07-24 14:12 UTCEPSS rescore
  4. 2026-07-23 14:14 UTCEPSS rescore
  5. 2026-07-23 00:56 UTCEG score recompute
  6. 2026-07-23 00:34 UTCEG score recompute
  7. 2026-07-23 00:00 UTCEG score recompute
  8. 2026-07-22 21:39 UTCEG score recompute
  9. 2026-07-20 17:03 UTCEPSS rescore
  10. 2026-07-18 09:59 UTCEPSS rescore
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  1. 2026-07-02 14:00 UTCEPSS rescore
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  47. 2026-06-01 13:49 UTCEPSS rescore
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  50. 2026-05-31 22:28 UTCEPSS rescore
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  52. 2026-05-31 00:13 UTCEPSS rescore
  53. 2026-05-31 00:13 UTCEPSS rescore
  54. 2026-05-30 22:03 UTCEG score recompute
  55. 2026-05-30 22:03 UTCVendor advisory
  56. 2026-05-30 22:03 UTCGHSA enrichment
  57. 2026-05-29 13:40 UTCEPSS rescore
  58. 2026-05-28 13:42 UTCEPSS rescore
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  74. 2026-05-18 21:29 UTCEPSS rescore

Frequently asked(4)

What is CVE-2008-1891?
CVE-2008-1891 is a medium vulnerability published on April 18, 2008. Directory traversal vulnerability in WEBrick in Ruby 1.8.4 and earlier, 1.8.5 before 1.8.5-p231, 1.8.6 before 1.8.6-p230, 1.8.7 before 1.8.7-p22, and 1.9.0 before 1.9.0-2, when using NTFS or FAT filesystems, allows remote attackers to read arbitrary CGI files via a trailing (1) + (plus), (2) %2b…
When was CVE-2008-1891 disclosed?
CVE-2008-1891 was first published in the National Vulnerability Database on April 18, 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-2008-1891 actively exploited?
CVE-2008-1891 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 3% probability of exploitation in the next 30 days, which ranks it in the top 15.0% of all scored CVEs.
How do I remediate CVE-2008-1891?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2008-1891, 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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