How severe is CVE-2005-1020?

CVE-2005-1020 has a CVSS 2.0 base score of 7.1, rated high severity.

Is CVE-2005-1020 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2005-1020?

CVE-2005-1020 primarily affects Cisco Ios. In total, 337 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2005-1020?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2005-1020 published?

CVE-2005-1020 was published on 2005-05-02 and last updated on 2026-06-16.

CVE-2005-1020

CVE-2005-1020 is a high-severity vulnerability in Cisco Ios with a CVSS 2.0 base score of 7.1. 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-287.

Key facts

Severity: High (CVSS 2.0 base score 7.1)
EPSS exploit prediction: 2% (75th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Cisco Ios
Published: 2005-05-02
Last modified: 2026-06-16

Description

Secure Shell (SSH) 2 in Cisco IOS 12.0 through 12.3 allows remote attackers to cause a denial of service (device reload) (1) via a username that contains a domain name when using a TACACS+ server to authenticate, (2) when a new SSH session is in the login phase and a currently logged in user issues a send command, or (3) when IOS is logging messages and an SSH session is terminated while the server is sending data.

Frequently asked questions

What is CVE-2005-1020?: Secure Shell (SSH) 2 in Cisco IOS 12.0 through 12.3 allows remote attackers to cause a denial of service (device reload) (1) via a username that contains a domain name when using a TACACS+ server to authenticate, (2) when a new SSH session is in the login phase and a currently logged in user issues a send command, or (3) when IOS is logging messages and an SSH session is terminated while the server is sending data.
How severe is CVE-2005-1020?: CVE-2005-1020 has a CVSS 2.0 base score of 7.1, rated high severity.
Is CVE-2005-1020 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2005-1020?: CVE-2005-1020 primarily affects Cisco Ios. In total, 337 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2005-1020?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2005-1020 published?: CVE-2005-1020 was published on 2005-05-02 and last updated on 2026-06-16.

References

Affected products (337)

cpe:2.3:o:cisco:ios:12.0:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(23\)s4:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(23\)s5:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(24\)s1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(24\)s4:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(24\)s5:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(24.2\)s:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(26\)s1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(27\)s:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(27\)sv:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(27\)sv1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0da:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0db:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0dc:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0s:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0sc:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0sl:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0sp:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0st:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0sv:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0sx:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0sy:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0sz:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0t:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0w5:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0wc:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0wt:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0wx:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0xa:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0xb:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0xc:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0xd:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0xe:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0xf:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0xg:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0xh:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0xi:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0xj:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0xk:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0xl:*:*:*:*:*:*:*

More vulnerabilities in Cisco Ios

CVE-2011-3271 — Critical (CVSS 10.0): Unspecified vulnerability in the Smart Install functionality in Cisco IOS 12.2 and 15.1 allows remote attackers to…
CVE-2011-0935 — Critical (CVSS 10.0): The PKI functionality in Cisco IOS 15.0 and 15.1 does not prevent permanent caching of certain public keys, which…
CVE-2010-1574 — Critical (CVSS 10.0): IOS 12.2(52)SE and 12.2(52)SE1 on Cisco Industrial Ethernet (IE) 3000 series switches has (1) a community name of…
CVE-2010-0581 — Critical (CVSS 10.0): Unspecified vulnerability in the SIP implementation in Cisco IOS 12.3 and 12.4 allows remote attackers to execute…
CVE-2010-0580 — Critical (CVSS 10.0): Unspecified vulnerability in the SIP implementation in Cisco IOS 12.3 and 12.4 allows remote attackers to execute…
CVE-2006-4950 — Critical (CVSS 10.0): Cisco IOS 12.2 through 12.4 before 20060920, as used by Cisco IAD2430, IAD2431, and IAD2432 Integrated Access Devices,…

All CVEs affecting Cisco Ios →

Other CWE-287 (Improper Authentication) vulnerabilities

CVE-2026-45480 — Critical (CVSS 10.0): Improper authentication in Azure Active Directory allows an unauthorized attacker to elevate privileges over a network.
CVE-2026-46389 — Critical (CVSS 10.0): UDS Identity Config builds the Keycloak configuration image (realm, plugins, theme, truststore, JARs) consumed by UDS…
CVE-2026-10611 — Critical (CVSS 10.0): An authentication bypass vulnerability exists in MISP when LDAP mixed authentication is enabled with OTP enforcement.…
CVE-2026-47280 — Critical (CVSS 10.0): Improper authentication in Azure Resource Manager (ARM) allows an unauthorized attacker to elevate privileges over a…
CVE-2026-42822 — Critical (CVSS 10.0): Improper authentication in Azure Local Disconnected Operations allows an unauthorized attacker to elevate privileges…
CVE-2026-20182 — Critical (CVSS 10.0): May 2026: This security advisory provides the details and fix information for a vulnerability that was discovered and…

Browse all CWE-287 (Improper Authentication) vulnerabilities →