How severe is CVE-2019-1842?

CVE-2019-1842 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2019-1842 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (65th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-1842?

CVE-2019-1842 primarily affects Cisco Ios Xr Firmware. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-1842?

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

When was CVE-2019-1842 published?

CVE-2019-1842 was published on 2019-06-05 and last updated on 2026-06-17.

CVE-2019-1842

CVE-2019-1842 is a medium-severity vulnerability in Cisco Ios Xr Firmware with a CVSS 3.x base score of 5.4. 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: Medium (CVSS 3.x base score 5.4)
CVSS v2: 5.5
EPSS exploit prediction: 1% (65th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Cisco Ios Xr Firmware
Published: 2019-06-05
Last modified: 2026-06-17

Description

A vulnerability in the Secure Shell (SSH) authentication function of Cisco IOS XR Software could allow an authenticated, remote attacker to successfully log in to an affected device using two distinct usernames. The vulnerability is due to a logic error that may occur when certain sequences of actions are processed during an SSH login event on the affected device. An attacker could exploit this vulnerability by initiating an SSH session to the device with a specific sequence that presents the two usernames. A successful exploit could result in logging data misrepresentation, user enumeration, or, in certain circumstances, a command authorization bypass. See the Details section for more information.

Frequently asked questions

What is CVE-2019-1842?: A vulnerability in the Secure Shell (SSH) authentication function of Cisco IOS XR Software could allow an authenticated, remote attacker to successfully log in to an affected device using two distinct usernames. The vulnerability is due to a logic error that may occur when certain sequences of actions are processed during an SSH login event on the affected device. An attacker could exploit this vulnerability by initiating an SSH session to the device with a specific sequence that presents the two usernames. A successful exploit could result in logging data misrepresentation, user enumeration, or, in certain circumstances, a command authorization bypass. See the Details section for more information.
How severe is CVE-2019-1842?: CVE-2019-1842 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2019-1842 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (65th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-1842?: CVE-2019-1842 primarily affects Cisco Ios Xr Firmware. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-1842?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2019-1842 published?: CVE-2019-1842 was published on 2019-06-05 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:o:cisco:ios_xr_firmware:6.1.2.tools:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xr_firmware:6.1.3.tools:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xr_firmware:6.2.3.tools:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xr_firmware:6.4.2.tools:*:*:*:*:*:*:*

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