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Vulnerabilities

Vulnerability · CVE-2009-2055

Cisco IOS XR Border Gateway Protocol (BGP) Denial-of-Service Vulnerability

Published Aug 19, 2009 · catalog updated Jun 16, 2026 · Cisco IOS XR

Patch now

CVE-2009-2055 is in the CISA known-exploited catalog, due Apr 15, 2022. Confirm Cisco IOS XR against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Severity
Medium5.9
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
3.31%
Remediation
Remediation guidance
Affected products
cpe cisco/ios xr · vendor Cisco IOS XR · vendor n/a n/a

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe cisco/ios xr3.4
  • cpe cisco/ios xr3.4.0
  • cpe cisco/ios xr3.4.1
  • cpe cisco/ios xr3.4.2
  • cpe cisco/ios xr3.4.3
  • cpe cisco/ios xr3.5
  • cpe cisco/ios xr3.5.2
  • cpe cisco/ios xr3.5.3
  • vendor Cisco IOS XRversion unspecified
  • vendor n/a n/aversion unspecified

How to fix CVE-2009-2055

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2009-2055 is in the CISA known-exploited catalog, due Apr 15, 2022. Confirm Cisco IOS XR against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with cisco/ios xr 3.4; cisco/ios xr 3.4.0; cisco/ios xr 3.4.1; cisco/ios xr 3.4.2. Apply updates per vendor instructions.

What should an analyst verify?

CWE-20: Improper Input Validation. EPSS 3.31%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Cisco security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Aug 19, 2009 · Catalog

    Detected

    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.

  2. Mar 25, 2022 · CISA KEV

    Known exploited

    Apply updates per vendor instructions.

  3. Apr 15, 2022 · CISA KEV

    Remediation due

    Apply updates per vendor instructions.

  4. Jun 16, 2026 · Catalog

    Updated

    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.

Sources

  • CISA KEVConfirmed exploitationCVE-2009-2055

    Cisco IOS XR,when BGP is the configured routing feature, allows remote attackers to cause a denial-of-service (DoS).

    cisa.gov
  • CVE.orgVulnerability recordCVE-2009-2055

    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.

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2009-2055

    30-day exploitation probability 3.3%

    first.org
  • NIST NVDVulnerability recordCVE-2009-2055

    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.

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2009-2055

    Cisco IOS XR,when BGP is the configured routing feature, allows remote attackers to cause a denial-of-service (DoS).

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.