medium
5.8
CWE
399
Advisory Published
Updated

CVE-2021-1377: Cisco IOS and IOS XE Software ARP Resource Management Exhaustion Denial of Service Vulnerability

First published: Wed Mar 24 2021(Updated: )

A vulnerability in Address Resolution Protocol (ARP) management of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to prevent an affected device from resolving ARP entries for legitimate hosts on the connected subnets. This vulnerability exists because ARP entries are mismanaged. An attacker could exploit this vulnerability by continuously sending traffic that results in incomplete ARP entries. A successful exploit could allow the attacker to cause ARP requests on the device to be unsuccessful for legitimate hosts, resulting in a denial of service (DoS) condition.

Credit: ykramarz@cisco.com

Affected SoftwareAffected VersionHow to fix
Cisco IOS=12.2\(6\)i1
Cisco IOS=15.1\(3\)svr1
Cisco IOS=15.1\(3\)svr2
Cisco IOS=15.1\(3\)svr3
Cisco IOS=15.1\(3\)svs
Cisco IOS=15.1\(3\)svs1
Cisco IOS=15.2\(2\)e6
Cisco IOS=15.2\(2\)e7
Cisco IOS=15.2\(2\)e7b
Cisco IOS=15.2\(2\)e8
Cisco IOS=15.2\(2\)e9
Cisco IOS=15.2\(2\)e9a
Cisco IOS=15.2\(2\)e10
Cisco IOS=15.2\(3\)e5
Cisco IOS=15.2\(4\)e4
Cisco IOS=15.2\(4\)e5
Cisco IOS=15.2\(4\)e5a
Cisco IOS=15.2\(4\)e6
Cisco IOS=15.2\(4\)e7
Cisco IOS=15.2\(4\)e8
Cisco IOS=15.2\(4\)e9
Cisco IOS=15.2\(4\)e10
Cisco IOS=15.2\(4\)e10a
Cisco IOS=15.2\(4\)ea6
Cisco IOS=15.2\(4\)ea7
Cisco IOS=15.2\(4\)ea8
Cisco IOS=15.2\(4\)ea9
Cisco IOS=15.2\(4\)ea9a
Cisco IOS=15.2\(4\)ea10
Cisco IOS=15.2\(5\)e1
Cisco IOS=15.2\(5\)e2
Cisco IOS=15.2\(5\)e2b
Cisco IOS=15.2\(5\)e2c
Cisco IOS=15.2\(5\)ex
Cisco IOS=15.2\(5a\)e1
Cisco IOS=15.2\(6\)e
Cisco IOS=15.2\(6\)e0a
Cisco IOS=15.2\(6\)e0c
Cisco IOS=15.2\(6\)e1
Cisco IOS=15.2\(6\)e1a
Cisco IOS=15.2\(6\)e1s
Cisco IOS=15.2\(6\)e2
Cisco IOS=15.2\(6\)e2a
Cisco IOS=15.2\(6\)e2b
Cisco IOS=15.2\(6\)e3
Cisco IOS=15.2\(6\)eb
Cisco IOS=15.2\(7\)e
Cisco IOS=15.2\(7\)e0a
Cisco IOS=15.2\(7\)e0b
Cisco IOS=15.2\(7\)e0s
Cisco IOS=15.2\(7\)e1
Cisco IOS=15.2\(7\)e1a
Cisco IOS=15.2\(7\)e2
Cisco IOS=15.2\(7\)e2a
Cisco IOS=15.2\(7\)e2b
Cisco IOS=15.2\(7\)e3
Cisco IOS=15.2\(7a\)e0b
Cisco IOS=15.2\(7b\)e0b
Cisco IOS=15.3\(3\)jpc97
Cisco IOS=15.4\(1\)sy
Cisco IOS=15.4\(1\)sy1
Cisco IOS=15.4\(1\)sy2
Cisco IOS=15.4\(1\)sy3
Cisco IOS=15.4\(1\)sy4
Cisco IOS=15.5\(1\)sy
Cisco IOS=15.5\(1\)sy1
Cisco IOS=15.5\(1\)sy2
Cisco IOS=15.5\(1\)sy3
Cisco IOS=15.5\(1\)sy4
Cisco IOS=15.5\(1\)sy5
Cisco IOS=15.5\(1\)sy6
Cisco IOS=15.5\(3\)m4
Cisco IOS=15.5\(3\)m4a
Cisco IOS=15.5\(3\)m4b
Cisco IOS=15.5\(3\)m4c
Cisco IOS=15.5\(3\)m5
Cisco IOS=15.5\(3\)m6
Cisco IOS=15.5\(3\)m6a
Cisco IOS=15.5\(3\)m7
Cisco IOS=15.5\(3\)m8
Cisco IOS=15.5\(3\)m9
Cisco IOS=15.5\(3\)m10
Cisco IOS=15.5\(3\)m11
Cisco IOS=15.5\(3\)s4
Cisco IOS=15.5\(3\)s5
Cisco IOS=15.5\(3\)s6
Cisco IOS=15.5\(3\)s6a
Cisco IOS=15.5\(3\)s6b
Cisco IOS=15.5\(3\)s7
Cisco IOS=15.5\(3\)s8
Cisco IOS=15.5\(3\)s9
Cisco IOS=15.5\(3\)s9a
Cisco IOS=15.5\(3\)s10
Cisco IOS=15.5\(3\)s10a
Cisco IOS=15.6\(3\)m2
Cisco IOS=15.6\(3\)m2a
Cisco IOS=15.6\(3\)m3
Cisco IOS=15.6\(3\)m3a
Cisco IOS=15.6\(3\)m4
Cisco IOS=15.6\(3\)m5
Cisco IOS=15.6\(3\)m6
Cisco IOS=15.6\(3\)m6a
Cisco IOS=15.6\(3\)m6b
Cisco IOS=15.6\(3\)m7
Cisco IOS=15.6\(3\)m8
Cisco IOS=15.6\(3\)m9
Cisco IOS=15.7\(3\)m
Cisco IOS=15.7\(3\)m0a
Cisco IOS=15.7\(3\)m1
Cisco IOS=15.7\(3\)m2
Cisco IOS=15.7\(3\)m3
Cisco IOS=15.7\(3\)m4
Cisco IOS=15.7\(3\)m4a
Cisco IOS=15.7\(3\)m4b
Cisco IOS=15.7\(3\)m5
Cisco IOS=15.7\(3\)m6
Cisco IOS=15.7\(3\)m7
Cisco IOS=15.8\(3\)m
Cisco IOS=15.8\(3\)m0a
Cisco IOS=15.8\(3\)m0b
Cisco IOS=15.8\(3\)m1
Cisco IOS=15.8\(3\)m1a
Cisco IOS=15.8\(3\)m2
Cisco IOS=15.8\(3\)m2a
Cisco IOS=15.8\(3\)m3
Cisco IOS=15.8\(3\)m3a
Cisco IOS=15.8\(3\)m3b
Cisco IOS=15.8\(3\)m4
Cisco IOS=15.8\(3\)m5
Cisco IOS=15.9\(3\)m
Cisco IOS=15.9\(3\)m0a
Cisco IOS=15.9\(3\)m1
Cisco IOS=15.9\(3\)m2
Cisco IOS=15.9\(3\)m2a
Cisco IOS XE Software=3.6.6e
Cisco IOS XE Software=3.6.7ae
Cisco IOS XE Software=3.6.7be
Cisco IOS XE Software=3.6.7e
Cisco IOS XE Software=3.6.8e
Cisco IOS XE Software=3.6.9ae
Cisco IOS XE Software=3.6.9e
Cisco IOS XE Software=3.6.10e
Cisco IOS XE Software=3.7.5e
Cisco IOS XE Software=3.8.4e
Cisco IOS XE Software=3.8.5ae
Cisco IOS XE Software=3.8.5e
Cisco IOS XE Software=3.8.6e
Cisco IOS XE Software=3.8.7e
Cisco IOS XE Software=3.8.8e
Cisco IOS XE Software=3.8.9e
Cisco IOS XE Software=3.8.10e
Cisco IOS XE Software=3.9.1e
Cisco IOS XE Software=3.9.2be
Cisco IOS XE Software=3.9.2e
Cisco IOS XE Software=3.10.0ce
Cisco IOS XE Software=3.10.0e
Cisco IOS XE Software=3.10.1ae
Cisco IOS XE Software=3.10.1e
Cisco IOS XE Software=3.10.1se
Cisco IOS XE Software=3.10.2e
Cisco IOS XE Software=3.10.3e
Cisco IOS XE Software=3.11.0e
Cisco IOS XE Software=3.11.1ae
Cisco IOS XE Software=3.11.1e
Cisco IOS XE Software=3.11.2ae
Cisco IOS XE Software=3.11.2e
Cisco IOS XE Software=3.11.3ae
Cisco IOS XE Software=3.11.3e
Cisco IOS XE Software=3.16.4as
Cisco IOS XE Software=3.16.4bs
Cisco IOS XE Software=3.16.4cs
Cisco IOS XE Software=3.16.4ds
Cisco IOS XE Software=3.16.4es
Cisco IOS XE Software=3.16.4gs
Cisco IOS XE Software=3.16.4s
Cisco IOS XE Software=3.16.5as
Cisco IOS XE Software=3.16.5bs
Cisco IOS XE Software=3.16.5s
Cisco IOS XE Software=3.16.6bs
Cisco IOS XE Software=3.16.6s
Cisco IOS XE Software=3.16.7as
Cisco IOS XE Software=3.16.7bs
Cisco IOS XE Software=3.16.7s
Cisco IOS XE Software=3.16.8s
Cisco IOS XE Software=3.16.9s
Cisco IOS XE Software=3.16.10as
Cisco IOS XE Software=3.16.10s
Cisco IOS XE Software=16.3.2
Cisco IOS XE Software=16.3.3
Cisco IOS XE Software=16.3.4
Cisco IOS XE Software=16.3.5
Cisco IOS XE Software=16.3.5b
Cisco IOS XE Software=16.3.6
Cisco IOS XE Software=16.3.7
Cisco IOS XE Software=16.3.8
Cisco IOS XE Software=16.3.9
Cisco IOS XE Software=16.3.10
Cisco IOS XE Software=16.3.11
Cisco IOS XE Software=16.4.1
Cisco IOS XE Software=16.4.2
Cisco IOS XE Software=16.4.3
Cisco IOS XE Software=16.5.1
Cisco IOS XE Software=16.5.1a
Cisco IOS XE Software=16.5.1b
Cisco IOS XE Software=16.5.2
Cisco IOS XE Software=16.5.3
Cisco IOS XE Software=16.6.1
Cisco IOS XE Software=16.6.2
Cisco IOS XE Software=16.6.3
Cisco IOS XE Software=16.6.4
Cisco IOS XE Software=16.6.4a
Cisco IOS XE Software=16.6.4s
Cisco IOS XE Software=16.6.5
Cisco IOS XE Software=16.6.5a
Cisco IOS XE Software=16.6.5b
Cisco IOS XE Software=16.6.6
Cisco IOS XE Software=16.6.7
Cisco IOS XE Software=16.6.7a
Cisco IOS XE Software=16.6.8
Cisco IOS XE Software=16.7.1
Cisco IOS XE Software=16.7.1a
Cisco IOS XE Software=16.7.1b
Cisco IOS XE Software=16.7.2
Cisco IOS XE Software=16.7.3
Cisco IOS XE Software=16.7.4
Cisco IOS XE Software=16.8.1
Cisco IOS XE Software=16.8.1a
Cisco IOS XE Software=16.8.1b
Cisco IOS XE Software=16.8.1c
Cisco IOS XE Software=16.8.1d
Cisco IOS XE Software=16.8.1e
Cisco IOS XE Software=16.8.1s
Cisco IOS XE Software=16.8.2
Cisco IOS XE Software=16.8.3
Cisco IOS XE Software=16.9.1
Cisco IOS XE Software=16.9.1a
Cisco IOS XE Software=16.9.1b
Cisco IOS XE Software=16.9.1c
Cisco IOS XE Software=16.9.1d
Cisco IOS XE Software=16.9.1s
Cisco IOS XE Software=16.9.2
Cisco IOS XE Software=16.9.2a
Cisco IOS XE Software=16.9.2s
Cisco IOS XE Software=16.9.3
Cisco IOS XE Software=16.9.3a
Cisco IOS XE Software=16.9.3h
Cisco IOS XE Software=16.9.3s
Cisco IOS XE Software=16.9.4
Cisco IOS XE Software=16.9.4c
Cisco IOS XE Software=16.9.5
Cisco IOS XE Software=16.9.5f
Cisco IOS XE Software=16.9.6
Cisco IOS XE Software=16.10.1
Cisco IOS XE Software=16.10.1a
Cisco IOS XE Software=16.10.1b
Cisco IOS XE Software=16.10.1c
Cisco IOS XE Software=16.10.1d
Cisco IOS XE Software=16.10.1e
Cisco IOS XE Software=16.10.1f
Cisco IOS XE Software=16.10.1g
Cisco IOS XE Software=16.10.1s
Cisco IOS XE Software=16.10.2
Cisco IOS XE Software=16.10.3
Cisco IOS XE Software=16.11.1
Cisco IOS XE Software=16.11.1a
Cisco IOS XE Software=16.11.1b
Cisco IOS XE Software=16.11.1c
Cisco IOS XE Software=16.11.1s
Cisco IOS XE Software=16.11.2
Cisco IOS XE Software=16.12.1
Cisco IOS XE Software=16.12.1a
Cisco IOS XE Software=16.12.1c
Cisco IOS XE Software=16.12.1s
Cisco IOS XE Software=16.12.1t
Cisco IOS XE Software=16.12.1w
Cisco IOS XE Software=16.12.1x
Cisco IOS XE Software=16.12.1y
Cisco IOS XE Software=16.12.1z
Cisco IOS XE Software=16.12.2
Cisco IOS XE Software=16.12.2a
Cisco IOS XE Software=16.12.2s
Cisco IOS XE Software=16.12.2t
Cisco IOS XE Software=16.12.3
Cisco IOS XE Software=16.12.3a
Cisco IOS XE Software=16.12.3s
Cisco IOS XE Software=16.12.4
Cisco IOS XE Software=16.12.4a
Cisco IOS XE Software=17.1.1
Cisco IOS XE Software=17.1.1a
Cisco IOS XE Software=17.1.1s
Cisco IOS XE Software=17.1.1t
Cisco IOS XE Software=17.1.2
Cisco IOS XE Software=17.2.1
Cisco IOS XE Software=17.2.1a
Cisco IOS XE Software=17.2.1r
Cisco IOS XE Software=17.2.1v
Cisco IOS XE Software=17.2.2
Cisco IOS XE Software=17.3.1
Cisco IOS XE Software=17.3.1a
Cisco IOS XE Software=17.3.1w
Cisco IOS XE Software=17.3.2
Cisco IOS XE Software=17.3.2a

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Reference Links

Frequently Asked Questions

  • What is the severity of CVE-2021-1377?

    The severity of CVE-2021-1377 is classified as high, allowing attackers to disrupt network operations.

  • How do I fix CVE-2021-1377?

    To fix CVE-2021-1377, update your Cisco IOS or IOS XE devices to the latest version that addresses this vulnerability.

  • What types of devices are affected by CVE-2021-1377?

    CVE-2021-1377 affects various Cisco IOS and IOS XE software versions as outlined in the advisory.

  • Is CVE-2021-1377 exploitable remotely?

    Yes, CVE-2021-1377 can be exploited by unauthenticated, remote attackers.

  • What impact does CVE-2021-1377 have on network operations?

    CVE-2021-1377 can prevent a device from resolving ARP entries for legitimate hosts, potentially leading to significant network disruptions.

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