The MPC::HexToNum function in helpctr.exe in Microsoft Windows Help and Support Center in Windows XP and Windows Server 2003 does not properly handle malformed escape sequences, which allows remote attackers to bypass the trusted documents whitelist (fromHCP option) and execute arbitrary commands via a crafted hcp:// URL, aka "Help Center URL Validation Vulnerability."
Published Jun 14, 2010
9.3
HIGHCVSS 2.0
EPSS 71.24%
Description
The MPC::HexToNum function in helpctr.exe in Microsoft Windows Help and Support Center in Windows XP and Windows Server 2003 does not properly handle malformed escape sequences, which allows remote attackers to bypass the trusted documents whitelist (fromHCP option) and execute arbitrary commands via a crafted hcp:// URL, aka "Help Center URL Validation Vulnerability."
Affected products
No data.
- n/a
- n/a
- n/a
- n/a
- n/a
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No data.
No Red Hat product state for this CVE.
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
No CVSS v3.0 score for this CVE.
AV:N/AC:M/Au:N/C:C/I:C/A:C
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
2022–2026- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (18 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 71.24% (0.71238) | 99.39th | v5 (v2026.06.15) |
| Sep 12, 2026 | 71.24% (0.71238) | 99.37th | v5 (v2026.06.15) |
| Aug 22, 2026 | 74.29% (0.74287) | 99.45th | v5 (v2026.06.15) |
| Jun 15, 2026 | 75.29% (0.75291) | 99.45th | v5 (v2026.06.15) |
| Mar 15, 2026 | 92.20% (0.92199) | 99.70th | v4 (v2025.03.14) |
| Oct 1, 2025 | 91.20% (0.91196) | 99.65th | v4 (v2025.03.14) |
| Mar 17, 2025 | 92.39% (0.92390) | 99.73th | v4 (v2025.03.14) |
| Dec 12, 2024 | 97.32% (0.97318) | 99.91th | v3 (v2023.03.01) |
| Jun 16, 2024 | 97.41% (0.97407) | 99.93th | v3 (v2023.03.01) |
| Mar 19, 2024 | 97.37% (0.97366) | 99.89th | v3 (v2023.03.01) |
| Feb 5, 2024 | 97.40% (0.97404) | 99.92th | v3 (v2023.03.01) |
| Dec 24, 2023 | 97.43% (0.97433) | 99.94th | v3 (v2023.03.01) |
| Sep 28, 2023 | 97.45% (0.97447) | 99.93th | v3 (v2023.03.01) |
| May 13, 2023 | 97.42% (0.97420) | 99.88th | v3 (v2023.03.01) |
| Mar 24, 2023 | 97.43% (0.97432) | 99.88th | v3 (v2023.03.01) |
| Mar 7, 2023 | 97.42% (0.97416) | 99.85th | v3 (v2023.03.01) |
| Mar 6, 2023 | 83.39% (0.83389) | 99.61th | v2 (v2022.01.01) |
| Feb 4, 2022 | 83.39% (0.83389) | 99.53th | v2 (v2022.01.01) |
References (16)
- http://archives.neohapsis.com/archives/fulldisclosure/2010-06/0197.html mailing-listx_refsource_FULLDISCExploit
- http://blogs.technet.com/b/msrc/archive/2010/06/10/windows-help-vulnerability-disclosure.aspx x_refsource_MISC
- http://blogs.technet.com/b/srd/archive/2010/06/10/help-and-support-center-vulnerability-full-disclosure-posting.aspx x_refsource_CONFIRMVendor Advisory
- http://secunia.com/advisories/40076 third-party-advisoryx_refsource_SECUNIAVendor Advisory
- http://www.exploit-db.com/exploits/13808 exploitx_refsource_EXPLOIT-DB
- http://www.kb.cert.org/vuls/id/578319 third-party-advisoryx_refsource_CERT-VNUS Government Resource
- http://www.microsoft.com/technet/security/advisory/2219475.mspx x_refsource_CONFIRMVendor Advisory
- http://www.securityfocus.com/archive/1/511774/100/0/threaded mailing-listx_refsource_BUGTRAQ
- http://www.securityfocus.com/archive/1/511783/100/0/threaded mailing-listx_refsource_BUGTRAQ
- http://www.securityfocus.com/bid/40725 vdb-entryx_refsource_BIDExploit
- http://www.securitytracker.com/id?1024084 vdb-entryx_refsource_SECTRACK
- http://www.us-cert.gov/cas/techalerts/TA10-194A.html third-party-advisoryx_refsource_CERTUS Government Resource
- http://www.vupen.com/english/advisories/2010/1417 vdb-entryx_refsource_VUPENVendor Advisory
- https://docs.microsoft.com/en-us/security-updates/securitybulletins/2010/ms10-042 vendor-advisoryx_refsource_MS
- https://exchange.xforce.ibmcloud.com/vulnerabilities/59267 vdb-entryx_refsource_XF
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11733 vdb-entrysignaturex_refsource_OVAL
Change history (0)
No recorded changes yet.