How severe is CVE-2011-2581?

CVE-2011-2581 has a CVSS 2.0 base score of 5.0, rated medium severity.

Is CVE-2011-2581 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2011-2581?

CVE-2011-2581 primarily affects Cisco Nx-os. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2011-2581?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2011-2581 published?

CVE-2011-2581 was published on 2011-09-14 and last updated on 2026-06-16.

CVE-2011-2581

CVE-2011-2581 is a medium-severity vulnerability in Cisco Nx-os with a CVSS 2.0 base score of 5.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-264.

Key facts

Severity: Medium (CVSS 2.0 base score 5.0)
EPSS exploit prediction: 2% (78th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-264
Affected product: Cisco Nx-os
Published: 2011-09-14
Last modified: 2026-06-16

Description

The ACL implementation in Cisco NX-OS 5.0(2) and 5.0(3) before 5.0(3)N2(1) on Nexus 5000 series switches, and NX-OS before 5.0(3)U1(2a) on Nexus 3000 series switches, does not properly handle comments in conjunction with deny statements, which allows remote attackers to bypass intended access restrictions in opportunistic circumstances by sending packets, aka Bug IDs CSCto09813 and CSCtr61490.

Frequently asked questions

What is CVE-2011-2581?: The ACL implementation in Cisco NX-OS 5.0(2) and 5.0(3) before 5.0(3)N2(1) on Nexus 5000 series switches, and NX-OS before 5.0(3)U1(2a) on Nexus 3000 series switches, does not properly handle comments in conjunction with deny statements, which allows remote attackers to bypass intended access restrictions in opportunistic circumstances by sending packets, aka Bug IDs CSCto09813 and CSCtr61490.
How severe is CVE-2011-2581?: CVE-2011-2581 has a CVSS 2.0 base score of 5.0, rated medium severity.
Is CVE-2011-2581 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2011-2581?: CVE-2011-2581 primarily affects Cisco Nx-os. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2011-2581?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2011-2581 published?: CVE-2011-2581 was published on 2011-09-14 and last updated on 2026-06-16.

References

Affected products (12)

cpe:2.3:a:cisco:nx-os:5.0\(2\):*:*:*:*:*:*:*
cpe:2.3:a:cisco:nx-os:5.0\(3\)n1\(1\):*:*:*:*:*:*:*
cpe:2.3:a:cisco:nx-os:5.0\(3\)n1\(1a\):*:*:*:*:*:*:*
cpe:2.3:a:cisco:nx-os:5.0\(3\)n1\(1b\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:5.0\(3\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:5.0\(3\)n1\(1c\):*:*:*:*:*:*:*
cpe:2.3:h:cisco:nexus_5000:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:5.0\(3\)u1\(1a\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:5.0\(3\)u1\(1b\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:5.0\(3\)u1\(1d\):*:*:*:*:*:*:*
cpe:2.3:h:cisco:nexus_3000:*:*:*:*:*:*:*:*

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