CVE-2009-2055

Improper Input Validation in Cisco IOS XR 3

Verified by Precogs Threat Research
Last Updated: Apr 22, 2026
Base Score
5.9MEDIUM

Executive Summary

CVE-2009-2055 is a medium severity vulnerability affecting appsec. It is classified as CWE-20. This vulnerability is actively being exploited in the wild.

Precogs AI Insight

"This security defect is primarily driven by within Cisco IOS XR 3., allowing bypassed validation checks on external interactions. By manipulating this weakness, a threat actor can gain unauthorized read or write access, effectively hijacking underlying configurations. Precogs AI Analysis Engine utilizes semantic code analysis to prevent unauthorized logical exploitation."

Exploit Probability (EPSS)
Low (0.8%)
Public POC
Available
Exploit Probability
Low (<10%)
Public POC
Actively Exploited
Affected Assets
appsecCWE-20

What is this vulnerability?

CVE-2009-2055 is categorized as a medium Improper Input Validation flaw with a CVSS base score of 5.9. Based on our vulnerability intelligence, this issue occurs when the application fails to securely handle untrusted data boundaries.

Cisco IOS XR 3.4.0 through 3.8.1 allows remote attackers to cause a denial of service (session reset) via a BGP UPDATE message with an invalid attribute, as demonstrated in the wild on 17 August 2009.

This architectural defect enables adversaries to bypass intended security controls, directly manipulating the application's execution state or data layer. Immediate strategic intervention is required.

Risk Assessment

MetricValue
CVSS Base Score5.9 (MEDIUM)
Vector StringCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
PublishedAugust 19, 2009
Last ModifiedApril 22, 2026
Related CWEsCWE-20, CWE-20

Impact on Systems

Data Exfiltration: Attackers can extract sensitive data from backend databases, configuration files, or internal services.

Authentication Bypass: Exploiting this flaw may allow unauthorized access to protected resources and administrative interfaces.

Lateral Movement: Once initial access is gained, attackers can pivot to internal systems and escalate privileges.

How to Fix and Mitigate CVE-2009-2055

  1. Apply Vendor Patches Immediately: This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog. Apply updates per vendor instructions.
  2. Verify Patch Deployment: Confirm all instances are updated using Precogs continuous monitoring.
  3. Review Audit Logs: Investigate historical access logs for indicators of compromise related to this attack surface.
  4. Implement Defense-in-Depth: Deploy WAF rules, network segmentation, and endpoint detection to limit blast radius.

Defending with Precogs AI

Precogs AI Analysis Engine identifies this vulnerability class through semantic code analysis powered by Code Property Graph (CPG) technology, performing inter-procedural taint tracking to detect injection flaws, broken authentication, and insecure data flows across your entire codebase.

Use Precogs to continuously scan your codebase, binaries, APIs, and infrastructure for this vulnerability class and related attack patterns. Our AI-powered detection engine combines static analysis with threat intelligence to identify exploitable weaknesses before attackers do.

Start scanning with Precogs →

Vulnerability Code Signature

Attack Data Flow

StageDetail
SourceUntrusted User Input
VectorInput flows through the application logic without sanitization
SinkExecution or Rendering Sink
ImpactApplication compromise, Logic Bypass, Data Exfiltration

Vulnerable Code Pattern

# ❌ VULNERABLE: Unsanitized Input Flow
def process_request(request):
    user_input = request.GET.get('data')
    # Taint sink: processing untrusted data
    execute_logic(user_input)
    return {"status": "success"}

Secure Code Pattern

# ✅ SECURE: Input Validation & Sanitization
def process_request(request):
    user_input = request.GET.get('data')
    
    # Sanitized boundary check
    if not is_valid_format(user_input):
        raise ValueError("Invalid input format")
        
    sanitized_data = sanitize(user_input)
    execute_logic(sanitized_data)
    return {"status": "success"}

How Precogs Detects This

Precogs AI Analysis Engine maps untrusted input directly to execution sinks to catch complex application security vulnerabilities.\n

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Is your system affected?

Precogs AI detects CVE-2009-2055 in compiled binaries, LLMs, and application layers — even without source code access.