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CVE DATABASE  /  CVE-2009-2055

CVE-2009-2055

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

CVSS 5.9 · MEDIUM ⚠ CISA KEV — ACTIVELY EXPLOITED
On the CISA KEV catalog

Confirmed exploited in the wild. Added 2022-03-25. Federal remediation due 2022-04-15.
Required action: Apply updates per vendor instructions.

Summary

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.

CVSS 3.1 breakdown

Base score5.9 (MEDIUM)
VectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vectorNETWORK
Attack complexityHIGH
Privileges requiredNONE
User interactionNONE
ScopeUNCHANGED
ConfidentialityNONE
IntegrityNONE
AvailabilityHIGH

Weakness type (CWE)

Affected products

Cisco ios xr
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References

Data: NIST NVD + CISA KEV. NVD last modified 2026-04-22. Always verify against the vendor advisory before acting.

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