Double free vulnerability in Microsoft Windows 2000, XP, 2003, and Vista allows local users to gain privileges by calling the MessageBox function with a MB_SERVICE_NOTIFICATION message with crafted data, which sends a HardError message to Client/Server Runtime Server Subsystem (CSRSS) process, which is not properly handled when invoking the UserHardError and GetHardErrorText functions in WINSRV.DLL.
CVE-2006-6696
This CVE was only ever scored under CVSS v2.0. NVD CVSS v2.0 base 6.9 — 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:L/AC:M/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 3.4% exploitation probability in the next 30 days, which is reflected in EG Risk but does not lift the v2 base. Confidence: LOW.
- Lower severity and no public exploit yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v2.0 (legacy)
- 6.9MEDIUMNVD never assigned a CVSS v3 rating to this CVE
- EG Score
- 6.9(low)
- EG Risk
- 62(Track)EG Risk 62/100SSVC: 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 computedSeverity69% × 45%Exploitation65% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 3%
- EPSS %ILE
- 88%
- KEV
- Not listed
Published
December 22, 2006
Last Modified
April 23, 2026
References (46)
- cve@mitrehttp://blogs.technet.com/msrc/archive/2006/12/22/new-report-of-a-windows-vulnerability.aspx
- cve@mitrehttp://groups.google.ca/group/microsoft.public.win32.programmer.kernel/browse_thread/thread/c5946bf40f227058/7bd7b5d66a4e5aff
- cve@mitrehttp://isc.sans.org/diary.php?n&storyid=1965
- cve@mitrehttp://lists.grok.org.uk/pipermail/full-disclosure/2006-December/051394.html
- cve@mitrehttp://research.eeye.com/html/alerts/zeroday/20061215.html
- cve@mitrehttp://secunia.com/advisories/23448
- cve@mitrehttp://securitytracker.com/id?1017433
- cve@mitrehttp://www.determina.com/security.research/vulnerabilities/csrss-harderror.html
- cve@mitrehttp://www.kuban.ru/forum_new/forum2/files/19124.html
- cve@mitrehttp://www.security.nnov.ru/Gnews944.html
- cve@mitrehttp://www.security.nnov.ru/files/messagebox.c
- cve@mitrehttp://www.securityfocus.com/archive/1/455061/100/0/threaded
- cve@mitrehttp://www.securityfocus.com/archive/1/455088/100/0/threaded
- cve@mitrehttp://www.securityfocus.com/archive/1/455104/100/0/threaded
- cve@mitrehttp://www.securityfocus.com/archive/1/455158/100/0/threaded
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 4× in last 7d / 5× 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.
- 2026-09-10 09:24 UTCEPSS rescore
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- 2026-05-31 05:13 UTCEG score recompute
- 2026-05-31 05:13 UTCGHSA enrichment
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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-3024✓ verifiedFirst seen Dec 27, 2006
Microsoft Windows - NtRaiseHardError 'Csrss.exe' Memory Disclosure
Open source ↗ - Exploit-DBEDB-2967✓ verifiedFirst seen Dec 20, 2006
Microsoft Windows - 'MessageBox' Memory Corruption Local Denial of Service
Open source ↗
Related CVEs(same CWE)
Same CWE
10 shownCWE-119
- CVE-2003-0819EG 10.0EPSS p99HIGH
- CVE-2003-0903EG 10.0EPSS p98HIGH
- CVE-2003-1339EG 10.0EPSS p99HIGH
- CVE-2003-0095EG 10.0EPSS p96HIGH
- CVE-2002-2227EG 10.0HIGH
- CVE-2002-2248EG 10.0EPSS p93HIGH
- CVE-2002-2250EG 10.0EPSS p94HIGH
- CVE-2002-2251EG 10.0EPSS p93HIGH
- CVE-2002-2253EG 10.0EPSS p93HIGH
- CVE-2002-2257EG 10.0EPSS p92HIGH
Frequently asked(4)
What is CVE-2006-6696?
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How do I remediate CVE-2006-6696?
Dependency Blast Radius
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