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CVE-2009-0635
Memory leak in the Cisco Tunneling Control Protocol (cTCP) encapsulation feature in Cisco IOS 12.4, when an Easy VPN (aka EZVPN) server is…
High7.1EPSS 2.5%
- Published
- Updated
- Reserved
- Assigned by
- cisco
Description
Memory leak in the Cisco Tunneling Control Protocol (cTCP) encapsulation feature in Cisco IOS 12.4, when an Easy VPN (aka EZVPN) server is enabled, allows remote attackers to cause a denial of service (memory consumption and device crash) via a sequence of TCP packets.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 2.0 | High7.1 | AV:N/AC:M/Au:N/C:N/I:N/A:C |
- EPSS (exploitation in 30 days)
- 2.5% · top 15% of all CVEs (4 Nov 2026)
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The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.1.
Weakness
Affected products
n/a
- affected n/a
References (7)
- http://www.cisco.com/en/US/products/products_security_advisory09186a0080a90469.shtml (opens in a new tab)x_refsource_CONFIRMx_transferred
- 20090325 Cisco IOS cTCP Denial of Service Vulnerability (opens in a new tab)vendor-advisoryx_refsource_CISCOx_transferred
- 34438 (opens in a new tab)third-party-advisoryx_refsource_SECUNIAx_transferred
- 34246 (opens in a new tab)vdb-entryx_refsource_BIDx_transferred
- ios-ctcp-dos(49417) (opens in a new tab)vdb-entryx_refsource_XFx_transferred
- 1021895 (opens in a new tab)vdb-entryx_refsource_SECTRACKx_transferred
- ADV-2009-0851 (opens in a new tab)vdb-entryx_refsource_VUPENx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2009-0635)Record last updated .