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Vulnerabilities

CriticalKEV

CVE-2023-20198 — Cisco IOS XE Web UI Privilege Escalation Vulnerability

CVE-2023-20198 · Cisco IOS XE Software · CVSS 10 · KEV

In brief

Severity · CVSS
Critical10CVSS 3.1, Critical
EPSS
100%
CISA KEV
Known exploited, listed since 16 Oct 2023
CERT-FR
No advisory or alert referenced in the catalog
Vendor
Cisco
Published · Modified
·
Last verified

Summary

Cisco is providing an update for the ongoing investigation into observed exploitation of the web UI feature in Cisco IOS XE Software. We are updating the list of fixed releases and adding the Software Checker. Our investigation has determined that the actors exploited two previously unknown issues. The attacker first exploited CVE-2023-20198 to gain initial access and issued a privilege 15 command to create a local user and password combination. This allowed the user to log in with normal user access. The attacker then exploited another component of the web UI feature, leveraging the new local user to elevate privilege to root and write the implant to the file system. Cisco has assigned CVE-2023-20273 to this issue. CVE-2023-20198 has been assigned a CVSS Score of 10.0. CVE-2023-20273 has been assigned a CVSS Score of 7.2. Both of these CVEs are being tracked by CSCwh87343.

Weakness: CWE-420

Title, description and the vendor's statements are quoted from the CVE record; a vendor's advisory is summarised in Patcharo's words, with a link.

Affected and fixed versions

Per product and release branch, as the vendor's CVE record and official advisory state them. A fixed release is shown only when a document names it: the vendor's, or CERT-FR's for Check Point, with its source.

4 branches with a published fixed release · 20 branches without a precise fixed release

Cisco IOS XE Software

Source: CVE-2023-20198cisco-sa-iosxe-webui-privesc-j22SaA4z

  1. 17.12
    Affected versions17.12.1, 17.12.1a
    First fixed releaseNot published in the sources followed
  2. 17.11
    Affected versions17.11.1, 17.11.1a
    First fixed releaseNot published in the sources followed
  3. 17.10
    Affected versions17.10.1, 17.10.1a, 17.10.1b
    First fixed releaseNot published in the sources followed
  4. 17.9
    Affected versions17.9.1, 17.9.1a, 17.9.1w, 17.9.1x
    10 releases listed17.9.1, 17.9.1a, 17.9.1w, 17.9.1x, 17.9.1y, 17.9.2, 17.9.2a, 17.9.3, 17.9.3a, 17.9.4
    First fixed release17.9.4a
  5. 17.8
    Affected versions17.8.1, 17.8.1a
    First fixed releaseNot published in the sources followed
  6. 17.7
    Affected versions17.7.1, 17.7.1a, 17.7.1b, 17.7.2
    First fixed releaseNot published in the sources followed
  7. 17.6
    Affected versions17.6.1, 17.6.1a, 17.6.1w, 17.6.1x
    12 releases listed17.6.1, 17.6.1a, 17.6.1w, 17.6.1x, 17.6.1y, 17.6.1z, 17.6.2, 17.6.3, 17.6.3a, 17.6.4, 17.6.5, 17.6.6
    First fixed release17.6.6a
  8. 17.5
    Affected versions17.5.1, 17.5.1a, 17.5.1b, 17.5.1c
    First fixed releaseNot published in the sources followed
  9. 17.4
    Affected versions17.4.1, 17.4.1a, 17.4.1b, 17.4.2
    5 releases listed17.4.1, 17.4.1a, 17.4.1b, 17.4.2, 17.4.2a
    First fixed releaseNot published in the sources followed
  10. 17.3
    Affected versions17.3.1, 17.3.1a, 17.3.1w, 17.3.1x
    18 releases listed17.3.1, 17.3.1a, 17.3.1w, 17.3.1x, 17.3.1z, 17.3.2, 17.3.2a, 17.3.3, 17.3.4, 17.3.4a, 17.3.4b, 17.3.4c, 17.3.5, 17.3.5a, 17.3.5b, 17.3.6, 17.3.7, 17.3.8
    First fixed release17.3.8a
  11. 17.2
    Affected versions17.2.1, 17.2.1a, 17.2.1r, 17.2.1v
    6 releases listed17.2.1, 17.2.1a, 17.2.1r, 17.2.1v, 17.2.2, 17.2.3
    First fixed releaseNot published in the sources followed
  12. 17.1
    Affected versions17.1.1, 17.1.1a, 17.1.1s, 17.1.1t
    5 releases listed17.1.1, 17.1.1a, 17.1.1s, 17.1.1t, 17.1.3
    First fixed releaseNot published in the sources followed
  13. 16.12
    Affected versions16.12.1, 16.12.1a, 16.12.1c, 16.12.1s
    25 releases listed16.12.1, 16.12.1a, 16.12.1c, 16.12.1s, 16.12.1t, 16.12.1w, 16.12.1x, 16.12.1y, 16.12.2, 16.12.2a, 16.12.2s, 16.12.3, 16.12.3a, 16.12.3s, 16.12.4, 16.12.4a, 16.12.5, 16.12.5a, 16.12.5b, 16.12.6, 16.12.6a, 16.12.7, 16.12.8, 16.12.9, 16.12.10
    Catalyst 3650 and 3850 only
    First fixed release16.12.10a
  14. 16.11
    Affected versions16.11.1, 16.11.1a, 16.11.1b, 16.11.1s
    5 releases listed16.11.1, 16.11.1a, 16.11.1b, 16.11.1s, 16.11.2
    First fixed releaseNot published in the sources followed
  15. 16.10
    Affected versions16.10.1, 16.10.1a, 16.10.1b, 16.10.1c
    11 releases listed16.10.1, 16.10.1a, 16.10.1b, 16.10.1c, 16.10.1d, 16.10.1e, 16.10.1f, 16.10.1g, 16.10.1s, 16.10.2, 16.10.3
    First fixed releaseNot published in the sources followed
  16. 16.9
    Affected versions16.9.1, 16.9.1a, 16.9.1b, 16.9.1s
    13 releases listed16.9.1, 16.9.1a, 16.9.1b, 16.9.1s, 16.9.2, 16.9.3, 16.9.3a, 16.9.4, 16.9.5, 16.9.5f, 16.9.6, 16.9.7, 16.9.8
    First fixed releaseNot published in the sources followed
  17. 16.8
    Affected versions16.8.1, 16.8.1a, 16.8.1b, 16.8.1c
    9 releases listed16.8.1, 16.8.1a, 16.8.1b, 16.8.1c, 16.8.1d, 16.8.1e, 16.8.1s, 16.8.2, 16.8.3
    First fixed releaseNot published in the sources followed
  18. 16.7
    Affected versions16.7.1, 16.7.1a, 16.7.1b, 16.7.2
    6 releases listed16.7.1, 16.7.1a, 16.7.1b, 16.7.2, 16.7.3, 16.7.4
    First fixed releaseNot published in the sources followed
  19. 16.6
    Affected versions16.6.1, 16.6.2, 16.6.3, 16.6.4
    12 releases listed16.6.1, 16.6.2, 16.6.3, 16.6.4, 16.6.4a, 16.6.5, 16.6.5a, 16.6.6, 16.6.7, 16.6.8, 16.6.9, 16.6.10
    First fixed releaseNot published in the sources followed
  20. 16.5
    Affected versions16.5.1, 16.5.1a, 16.5.1b, 16.5.2
    5 releases listed16.5.1, 16.5.1a, 16.5.1b, 16.5.2, 16.5.3
    First fixed releaseNot published in the sources followed
  21. 16.4
    Affected versions16.4.1, 16.4.2, 16.4.3
    First fixed releaseNot published in the sources followed
  22. 16.3
    Affected versions16.3.1, 16.3.1a, 16.3.2, 16.3.3
    13 releases listed16.3.1, 16.3.1a, 16.3.2, 16.3.3, 16.3.4, 16.3.5, 16.3.5b, 16.3.6, 16.3.7, 16.3.8, 16.3.9, 16.3.10, 16.3.11
    First fixed releaseNot published in the sources followed
  23. 16.2
    Affected versions16.2.1, 16.2.2
    First fixed releaseNot published in the sources followed
  24. 16.1
    Affected versions16.1.1, 16.1.2, 16.1.3
    First fixed releaseNot published in the sources followed

Remediation

Fix available

Vendor fix

  • IOS XE Software 17.917.9.4a
  • IOS XE Software 17.617.6.6a
  • IOS XE Software 17.317.3.8a
  • IOS XE Software 16.1216.12.10a

Upgrade to a fixed release listed above for your branch, or to a later fixed release the vendor explicitly supports.

Cisco has released updates that fix this vulnerability; its advisory lists them.

SourceCisco Security Advisory cisco-sa-iosxe-webui-privesc-j22SaA4z

Workarounds (vendor)

Cisco states in its advisory that no workaround is available.

SourceCisco Security Advisory cisco-sa-iosxe-webui-privesc-j22SaA4z

CISA KEV required action

Verify that instances of Cisco IOS XE Web UI are in compliance with BOD 23-02 and apply mitigations per vendor instructions. For affected products (Cisco IOS XE Web UI exposed to the internet or to untrusted networks), follow vendor instructions to determine if a system may have been compromised and immediately report positive findings to CISA.

CISA due date:

SourceCISA KEV

Last verified 1 Oct 2026 at 09:29 UTC

Known exploitation

Added to CISA KEV on 16 Oct 2023

Federal remediation due date: 20 Oct 2023

The CISA required action is shown under Remediation.

100% probability of exploitation in the next 30 days (percentile 100%).

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CERT-FR

No CERT-FR advisory or alert of the last two years references this CVE, for the vendors Patcharo covers.

Timeline

  1. Added to CISA KEV
  2. Published by the source
  3. CISA remediation due date
  4. Source record last modified
  5. EPSS score computed
  6. Last verified by Patcharo

Official sources

References

Cisco · CISA Known Exploited Vulnerabilities · NVD · FIRST EPSS · Cisco Security Advisory cisco-sa-iosxe-webui-privesc-j22SaA4z

How Patcharo reads this

Affected and fixed releases come from the vendor's structured statements and are matched against exact versions; CVSS from NVD, exploitation from CISA KEV and the vendor's own advisory, probability from FIRST EPSS. Missing data stays Unknown and never becomes Not affected.

Read the methodologyRead the guide: Cisco Secure Firewall release trains: Threat Defense, Management Center and ASA versions explained