Cisco PIX 6.3 and 7.0 allows remote attackers to cause a denial of service (blocked new connections) via spoofed TCP packets that cause the PIX to create embryonic connections that that would not produce a valid connection with the end system, including (1) SYN packets with invalid checksums, which do not result in a RST; or, from an external interface, (2) one byte of "meaningless data," or (3) a TTL that is one less than needed to reach the internal destination.
CVE-2005-3774
- No confirmed exploitation signals yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- —
- EG Score
- 0.0(none)
- EPSS
- 96.9%
- KEV
- Not listed
Published
November 23, 2005
Last Modified
April 16, 2026
References (32)
- cve@mitrehttp://lists.grok.org.uk/pipermail/full-disclosure/2005-November/038971.html
- cve@mitrehttp://lists.grok.org.uk/pipermail/full-disclosure/2005-November/038983.html
- cve@mitrehttp://secunia.com/advisories/17670
- cve@mitrehttp://securitytracker.com/id?1015256
- cve@mitrehttp://www.cisco.com/en/US/products/hw/vpndevc/ps2030/products_security_notice09186a0080624a37.html
- cve@mitrehttp://www.cisco.com/warp/public/707/cisco-response-20051122-pix.shtml
- cve@mitrehttp://www.kb.cert.org/vuls/id/853540
- cve@mitrehttp://www.osvdb.org/24140
- cve@mitrehttp://www.securityfocus.com/archive/1/417458/30/0/threaded
- cve@mitrehttp://www.securityfocus.com/archive/1/426989/100/0/threaded
- cve@mitrehttp://www.securityfocus.com/archive/1/426991/100/0/threaded
- cve@mitrehttp://www.securityfocus.com/archive/1/427041/100/0/threaded
- cve@mitrehttp://www.securityfocus.com/bid/15525
- cve@mitrehttp://www.vupen.com/english/advisories/2005/2546
- cve@mitrehttps://exchange.xforce.ibmcloud.com/vulnerabilities/25077
Data Freshness Timeline
(refreshed 6× in last 7d / 27× 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.
- 2026-07-13 22:24 UTCEPSS rescore
- 2026-07-13 06:07 UTCEPSS rescore
- 2026-07-13 06:07 UTCEPSS rescore
- 2026-07-11 08:22 UTCEPSS rescore
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- 2026-07-08 15:09 UTCEPSS rescore
- 2026-07-02 14:00 UTCEPSS rescore
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- 2026-06-29 14:02 UTCEPSS rescore
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- 2026-06-28 04:52 UTCEPSS rescore
- 2026-06-27 03:04 UTCEPSS rescore
- 2026-06-25 13:46 UTCEPSS rescore
- 2026-06-24 14:01 UTCEPSS rescore
- 2026-06-23 21:29 UTCEPSS rescore
- 2026-06-22 14:22 UTCEPSS rescore
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- 2026-06-21 01:56 UTCEPSS rescore
- 2026-06-18 17:49 UTCEPSS rescore
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- 2026-06-17 17:49 UTCEPSS rescore
- 2026-06-17 17:49 UTCEPSS rescore
- 2026-06-16 17:49 UTCEPSS rescore
- 2026-06-16 17:49 UTCEPSS rescore
- 2026-06-15 17:44 UTCEPSS rescore
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- 2026-06-14 23:13 UTCEPSS rescore
- 2026-06-14 23:13 UTCEPSS rescore
- 2026-06-13 22:56 UTCEPSS rescore
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- 2026-06-11 13:55 UTCEPSS rescore
- 2026-06-10 22:14 UTCEPSS rescore
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- 2026-06-07 15:21 UTCEPSS rescore
- 2026-06-06 13:44 UTCEPSS rescore
- 2026-06-06 13:44 UTCEPSS rescore
- 2026-06-05 22:43 UTCEPSS rescore
- 2026-06-05 22:43 UTCEPSS rescore
- 2026-06-05 06:07 UTCEPSS rescore
- 2026-06-05 06:07 UTCEPSS rescore
- 2026-06-04 13:09 UTCEPSS rescore
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- 2026-06-02 20:10 UTCEPSS rescore
- 2026-06-02 20:10 UTCEPSS rescore
- 2026-05-31 22:28 UTCEPSS rescore
- 2026-05-31 11:31 UTCEG score recompute
- 2026-05-31 11:31 UTCGHSA enrichment
- 2026-05-31 00:13 UTCEPSS rescore
- 2026-05-31 00:13 UTCEPSS rescore
- 2026-05-29 13:40 UTCEPSS rescore
- 2026-05-29 13:40 UTCEPSS rescore
- 2026-05-28 13:42 UTCEPSS rescore
- 2026-05-28 13:42 UTCEPSS rescore
- 2026-05-28 13:42 UTCEPSS rescore
- 2026-05-27 13:37 UTCEPSS rescore
- 2026-05-26 07:16 UTCEPSS rescore
- 2026-05-26 07:16 UTCEPSS rescore
- 2026-05-22 21:15 UTCEPSS rescore
- 2026-05-21 22:38 UTCEPSS rescore
- 2026-05-20 22:36 UTCEPSS rescore
- 2026-05-20 22:36 UTCEPSS rescore
- 2026-05-20 11:20 UTCEPSS rescore
- 2026-05-20 11:20 UTCEPSS rescore
- 2026-05-18 21:29 UTCEPSS rescore
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-1338✓ verifiedFirst seen Nov 23, 2005
Cisco PIX - Spoofed TCP SYN Packets Remote Denial of Service
Open source ↗ - Exploit-DBEDB-26548✓ verifiedFirst seen Nov 22, 2005
Cisco PIX - TCP SYN Packet Denial of Service
Open source ↗
Frequently asked(4)
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