CVE-1999-0775

CRITICAL

Cisco Gigabit Switch routers running IOS allow remote attackers to forward unauthorized packets due to improper handling of the "established" keyword in an access list.

Affects 1 product across 1 vendor.

BCS7.57
CVSS 2.010.0
EPSS3.1%
Percentile86th
PatchUnknown
CVSS Vector — Plain English Remotely exploitable over the network, low complexity.
◆ SAGE Intelligence — CITED Relevance Research Team

This vulnerability was disclosed in 1999. A critical vulnerability affects Cisco systems (CVE-1999-0775). No public exploit code is currently available. Isolate affected systems if patching is not feasible.

BSID: BS-1999-GLOBAL-308057-C • Model: rule-based-v1 • Confidence: MEDIUM

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Frequently Asked Questions
What is CVE-1999-0775?
This vulnerability was disclosed in 1999. A critical vulnerability affects Cisco systems (CVE-1999-0775). No public exploit code is currently available. Isolate affected systems if patching is not feasible.
What is the CVSS score for CVE-1999-0775?
CVE-1999-0775 has CVSS 10.0 (Critical). Vector: AV:N/AC:L/Au:N/C:C/I:C/A:C. EPSS: 3.1%.
Is CVE-1999-0775 actively exploited?
No confirmed active exploitation of CVE-1999-0775 as of 2026-06-20.
How do I remediate CVE-1999-0775?
Priority: MEDIUM.
What systems are affected by CVE-1999-0775?
CVE-1999-0775 affects: Cisco.
Vulnerability Details
CVE IDCVE-1999-0775
BSIDBS-1999-GLOBAL-308057-C BreachSpider Global ID
CVSS VectorAV:N/AC:L/Au:N/C:C/I:C/A:C
Published1999-06-10
Last Modified2026-06-16
ICS Relevance65%
Domains
NETWORK-INFRA
SourceNVD
Official Description

Cisco Gigabit Switch routers running IOS allow remote attackers to forward unauthorized packets due to improper handling of the "established" keyword in an access list.

Source: NIST NVD / MITRE CVE Database

Attack Vector Analysis — CITED Relevance

Vulnerability details: Cisco Gigabit Switch routers running IOS allow remote attackers to forward unauthorized packets due to improper handling of the "established" keyword in an access list. CVSS vector: AV:N/AC:L/Au:N/C:C/I:C/A:C.

Exploitation Likelihood: LOW

Affected Products
VendorProductFixed Version
Cisco Ios —
Remediation

No patch URL on record. Monitor vendor security advisories directly.

Threat Intelligence
● Threat Intelligence Validated: July 2026 | Threat Age: 9907 Days
CISA KEVNot in KEV catalog
Public ExploitNot confirmed
PoC CodeNot confirmed
SAGE Enrichment Record — provenance & audit hash
Modelrule-based-v1
ConfidenceMEDIUM
Enriched At2026-05-24
SHA-512 Audit Hash3ece2e8f69319fffc6fcdffb0f484fb025c07c01eeadc872f4ebed78bb2fc7564356c5a0b66c0a0e168428acd88fbc56d824f4fed9d51788da187790c9c7766e
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