CVE-2021-1620

High

Description

A vulnerability in the Internet Key Exchange Version 2 (IKEv2) support for the AutoReconnect feature of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated, remote attacker to exhaust the free IP addresses from the assigned local pool. This vulnerability occurs because the code does not release the allocated IP address under certain failure conditions. An attacker could exploit this vulnerability by trying to connect to the device with a non-AnyConnect client. A successful exploit could allow the attacker to exhaust the IP addresses from the assigned local pool, which prevents users from logging in and leads to a denial of service (DoS) condition.

SeverityHigh
CVSS7.7
Exploit probability—
ProductCisco Ios
PublishedSep 23, 2021
First seenSep 23, 2021
Weakness typeCWE-563CWE-563

How to fix

Affected products

ProductAffected versionsFixed in
cisco ios12.2\(6\)i1, 15.1\(3\)svr1, 15.1\(3\)svr2, 15.1\(3\)svr3, 15.1\(3\)svs, 15.1\(3\)svs1, 15.1\(3\)svt1, 15.1\(3\)svt2, 15.1\(3\)svu1, 15.2\(1\)sy2, 15.2\(1\)sy3, 15.2\(1\)sy4, 15.2\(1\)sy5, 15.2\(1\)sy6, 15.2\(1\)sy7, 15.2\(1\)sy8, 15.2\(4\)e, 15.2\(4\)e1, 15.2\(4\)e2, 15.2\(4\)e3, 15.2\(4\)e4, 15.2\(4\)e5, 15.2\(4\)e5a, 15.2\(4\)e6, 15.2\(4\)e7, 15.2\(4\)e8, 15.2\(4\)e9, 15.2\(4\)e10, 15.2\(4\)e10a, 15.2\(4\)e10b, 15.2\(4\)ea, 15.2\(4\)ea1, 15.2\(4\)ea2, 15.2\(4\)ea3, 15.2\(4\)ea4, 15.2\(4\)ea5, 15.2\(4\)ea6, 15.2\(4\)ea7, 15.2\(4\)ea8, 15.2\(4\)ea9, 15.2\(4\)ea9a, 15.2\(4\)ec1, 15.2\(4\)ec2, 15.2\(4m\)e1, 15.2\(4m\)e2, 15.2\(4m\)e3, 15.2\(4n\)e2, 15.2\(4o\)e2, 15.2\(4o\)e3, 15.2\(4p\)e1, 15.2\(4q\)e1, 15.2\(4s\)e1, 15.2\(5\)e, 15.2\(5\)e1, 15.2\(5\)e2, 15.2\(5\)e2b, 15.2\(5\)e2c, 15.2\(5\)ea, 15.2\(5\)ex, 15.2\(5a\)e, 15.2\(5a\)e1, 15.2\(5b\)e, 15.2\(5c\)e, 15.2\(6\)e, 15.2\(6\)e0a, 15.2\(6\)e0c, 15.2\(6\)e1, 15.2\(6\)e1a, 15.2\(6\)e1s, 15.2\(6\)e2, 15.2\(6\)e2a, 15.2\(6\)e2b, 15.2\(6\)e3, 15.2\(6\)eb, 15.2\(7\)e, 15.2\(7\)e0a, 15.2\(7\)e0b, 15.2\(7\)e0s, 15.2\(7\)e1, 15.2\(7\)e1a, 15.2\(7\)e2, 15.2\(7\)e2a, 15.2\(7\)e2b, 15.2\(7\)e3, 15.2\(7\)e3a, 15.2\(7\)e3k, 15.2\(7\)e4, 15.2\(7\)e5, 15.2\(7\)e99, 15.2\(7a\)e0b, 15.2\(7b\)e0b, 15.2\(8\)e, 15.2\(8\)e1, 15.2\(234k\)e, 15.3\(0\)sy, 15.3\(1\)sy, 15.3\(1\)sy1, 15.3\(1\)sy2, 15.3\(3\)jc6, 15.3\(3\)jc8, 15.3\(3\)jc9, 15.3\(3\)jc14, 15.3\(3\)jca7, 15.3\(3\)jca8, 15.3\(3\)jca9, 15.3\(3\)jd3, 15.3\(3\)jd4, 15.3\(3\)jd5, 15.3\(3\)jd6, 15.3\(3\)jd7, 15.3\(3\)jd8, 15.3\(3\)jd9, 15.3\(3\)jd11, 15.3\(3\)jd12, 15.3\(3\)jd13, 15.3\(3\)jd14, 15.3\(3\)jd16, 15.3\(3\)jd17, 15.3\(3\)jda7, 15.3\(3\)jda8, 15.3\(3\)jda9, 15.3\(3\)jda11, 15.3\(3\)jda12, 15.3\(3\)jda13, 15.3\(3\)jda14, 15.3\(3\)jda16, 15.3\(3\)jda17, 15.3\(3\)je, 15.3\(3\)jf, 15.3\(3\)jf1, 15.3\(3\)jf2, 15.3\(3\)jf4, 15.3\(3\)jf5, 15.3\(3\)jf6, 15.3\(3\)jf7, 15.3\(3\)jf8, 15.3\(3\)jf9, 15.3\(3\)jf10, 15.3\(3\)jf11, 15.3\(3\)jf12, 15.3\(3\)jf12i, 15.3\(3\)jf14, 15.3\(3\)jf14i, 15.3\(3\)jf15, 15.3\(3\)jg, 15.3\(3\)jg1, 15.3\(3\)jh, 15.3\(3\)jh1, 15.3\(3\)ji1, 15.3\(3\)ji3, 15.3\(3\)ji4, 15.3\(3\)ji5, 15.3\(3\)ji6, 15.3\(3\)jj, 15.3\(3\)jj1, 15.3\(3\)jk, 15.3\(3\)jk1, 15.3\(3\)jk1t, 15.3\(3\)jk2, 15.3\(3\)jk2a, 15.3\(3\)jk3, 15.3\(3\)jk4, 15.3\(3\)jk5, 15.3\(3\)jk6, 15.3\(3\)jk100, 15.3\(3\)jn13, 15.3\(3\)jn14, 15.3\(3\)jn15, 15.3\(3\)jpc5, 15.3\(3\)jpi1, 15.3\(3\)jpi1t, 15.3\(3\)jpi4, 15.3\(3\)jpi5, 15.3\(3\)jpi5s, 15.3\(3\)jpi6a, 15.3\(3\)jpi7, 15.3\(3\)jpi8, 15.3\(3\)jpj2, 15.3\(3\)jpj2t, 15.3\(3\)jpj3, 15.3\(3\)jpj3a, 15.3\(3\)jpj4, 15.3\(3\)jpj5, 15.3\(3\)jpj6, 15.3\(3\)jpj7, 15.3\(3\)jpk, 15.3\(3\)jpk1, 15.3\(3\)jpk2, 15.4\(1\)cg, 15.4\(1\)cg1, 15.4\(1\)s, 15.4\(1\)s1, 15.4\(1\)s2, 15.4\(1\)s3, 15.4\(1\)s4, 15.4\(1\)sy, 15.4\(1\)sy1, 15.4\(1\)sy2, 15.4\(1\)sy3, 15.4\(1\)sy4—

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