How severe is CVE-2009-2055?

CVE-2009-2055 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2009-2055 being actively exploited?

Yes. CVE-2009-2055 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2022-03-25, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2009-2055?

CVE-2009-2055 primarily affects Cisco Ios Xr. In total, 19 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2009-2055?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2009-2055 have an EU (EUVD) identifier?

Yes. CVE-2009-2055 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2009-2051. It is also flagged as exploited in the EUVD (since 2022-03-25).

When was CVE-2009-2055 published?

CVE-2009-2055 was published on 2009-08-19 and last updated on 2026-06-16.

CVE-2009-2055

CVE-2009-2055 is a medium-severity vulnerability in Cisco Ios Xr with a CVSS 3.x base score of 5.9. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2022-03-25). The underlying weakness is classified as CWE-20.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
CVSS v2: 4.3
EPSS exploit prediction: 3% (87th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2022-03-25)
EU (EUVD) id: EUVD-2009-2051
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2022-03-25)
Weakness: CWE-20
Affected product: Cisco Ios Xr
Published: 2009-08-19
Last modified: 2026-06-16

Description

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.

Frequently asked questions

What is CVE-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.
How severe is CVE-2009-2055?: CVE-2009-2055 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2009-2055 being actively exploited?: Yes. CVE-2009-2055 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2022-03-25, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2009-2055?: CVE-2009-2055 primarily affects Cisco Ios Xr. In total, 19 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2009-2055?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2009-2055 have an EU (EUVD) identifier?: Yes. CVE-2009-2055 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2009-2051. It is also flagged as exploited in the EUVD (since 2022-03-25).
When was CVE-2009-2055 published?: CVE-2009-2055 was published on 2009-08-19 and last updated on 2026-06-16.

References

Affected products (19)

cpe:2.3:o:cisco:ios_xr:3.4:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xr:3.4.0:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xr:3.4.1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xr:3.4.2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xr:3.4.3:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xr:3.5:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xr:3.5.2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xr:3.5.3:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xr:3.5.4:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xr:3.6.0:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xr:3.6.1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xr:3.6.2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xr:3.6.3:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xr:3.7.0:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xr:3.7.1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xr:3.7.2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xr:3.7.3:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xr:3.8.0:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xr:3.8.1:*:*:*:*:*:*:*

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