Microsoft Internet Information Services (IIS) 5.x and 6.x uses only the portion of a filename before a ; (semicolon) character to determine the file extension, which allows remote attackers to bypass intended extension restrictions of third-party upload applications via a filename with a (1) .asp, (2) .cer, or (3) .asa first extension, followed by a semicolon and a safe extension, as demonstrated by the use of asp.dll to handle a .asp;.jpg file.
CVE-2009-4444
This CVE was only ever scored under CVSS v2.0. NVD CVSS v2.0 base 6.0 — 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:M/Au:S/C:P/I:P/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 63.6% exploitation probability in the next 30 days, which is reflected in EG Risk but does not lift the v2 base. Confidence: LOW.
- 255 internet-exposed hosts are running an affected version right now
- High exploitation likelihood — EPSS 64%
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
255 internet-exposed hosts are running an affected version of CVE-2009-4444 right now.
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)
- 6.0MEDIUMNVD never assigned a CVSS v3 rating to this CVE
- EG Score
- 6.0(low)
- EG Risk
- 57(Track)EG Risk 57/100SSVC: 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 computedSeverity60% × 45%Exploitation64% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 64%
- EPSS %ILE
- 99%
- KEV
- Not listed
Published
December 29, 2009
Last Modified
April 23, 2026
References (12)
- cve@mitrehttp://blogs.technet.com/msrc/archive/2009/12/27/new-reports-of-a-vulnerability-in-iis.aspx
- cve@mitrehttp://secunia.com/advisories/37831
- cve@mitrehttp://securitytracker.com/id?1023387
- cve@mitrehttp://soroush.secproject.com/downloadable/iis-semicolon-report.pdf
- cve@mitrehttp://www.securityfocus.com/bid/37460
- cve@mitrehttp://www.vupen.com/english/advisories/2009/3634
- af854a3a-2127-422b-91ae-364da2661108http://blogs.technet.com/msrc/archive/2009/12/27/new-reports-of-a-vulnerability-in-iis.aspx
- af854a3a-2127-422b-91ae-364da2661108http://secunia.com/advisories/37831
- af854a3a-2127-422b-91ae-364da2661108http://securitytracker.com/id?1023387
- af854a3a-2127-422b-91ae-364da2661108http://soroush.secproject.com/downloadable/iis-semicolon-report.pdf
- af854a3a-2127-422b-91ae-364da2661108http://www.securityfocus.com/bid/37460
- af854a3a-2127-422b-91ae-364da2661108http://www.vupen.com/english/advisories/2009/3634
Data Freshness Timeline
(refreshed 2× in last 7d / 9× 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.
- 2026-08-26 14:40 UTCEPSS rescore
- 2026-08-25 13:43 UTCEPSS rescore
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- 2026-07-26 13:39 UTCEG score recompute▲ 6.00
- 2026-07-25 14:12 UTCEPSS rescore
- 2026-07-23 14:14 UTCEPSS rescore
- 2026-07-23 01:00 UTCEG score recompute
- 2026-07-23 00:37 UTCEG score recompute▼ 5.50
- 2026-07-23 00:05 UTCEG score recompute▲ 5.50
- 2026-07-22 21:44 UTCEG score recompute
- 2026-07-22 14:03 UTCEPSS rescore
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- 2026-05-29 13:14 UTCEG score recompute
- 2026-05-29 13:14 UTCGHSA enrichment
- 2026-05-28 13:42 UTCEPSS rescore
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Frequently asked(4)
What is CVE-2009-4444?
When was CVE-2009-4444 disclosed?
Is CVE-2009-4444 actively exploited?
How do I remediate CVE-2009-4444?
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