Unverified image boot via manipulated iPXE parameters
Published Sep 13, 2023 · Updated Dec 16, 2025
Improper signature verification in Cisco IOS XR Software allows local users to boot an unverified image through the iPXE function. The iPXE boot path insufficiently verifies image signatures when boot parameters controlling verification are manipulated, so the device accepts and starts an untrusted software image. An authenticated local user with high privileges must control those parameters; a successful boot runs the unverified image as the device software.
Summary
What happened
Improper signature verification in Cisco IOS XR Software allows local users to boot an unverified image through the iPXE function. The iPXE boot path insufficiently verifies image signatures when boot parameters controlling verification are manipulated, so the device accepts and starts an untrusted software image. An authenticated local user with high privileges must control those parameters; a successful boot runs the unverified image as the device software.
The record
- CVE
- CVE-2023-20236
- Published
- Sep 13, 2023
- Updated
- Dec 16, 2025
- Vendor
- ClamAV
- Product
- Cisco IOS XR Software
- Classifications
- CWE-347, CWE-345, T1601.001
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Sep 13, 2023CVE publishedPublication date reported by the CVE source.
- Dec 16, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <=7.9.2
- Affected versionversion=5.2.0
- Affected versionversion=5.2.1
- Affected versionversion=5.2.2
- Affected versionversion=5.2.3
- Affected versionversion=5.2.4
- Affected versionversion=5.2.47
- Affected versionversion=5.2.5
- Affected versionversion=5.3.0
- Affected versionversion=5.3.1
- Affected versionversion=5.3.2
- Affected versionversion=5.3.3
- Affected versionversion=5.3.4
- Affected versionversion=6.0.0
- Affected versionversion=6.0.1
- Affected versionversion=6.0.2
- Affected versionversion=6.1.1
- Affected versionversion=6.1.12
- Affected versionversion=6.1.2
- Affected versionversion=6.1.22
- Affected versionversion=6.1.3
- Affected versionversion=6.1.32
- Affected versionversion=6.1.36
- Affected versionversion=6.1.4
- Affected versionversion=6.1.42
- Affected versionversion=6.2.1
- Affected versionversion=6.2.11
- Affected versionversion=6.2.2
- Affected versionversion=6.2.25
- Affected versionversion=6.2.3
- Affected versionversion=6.3.15
- Affected versionversion=6.3.2
- Affected versionversion=6.3.3
- Affected versionversion=6.4.1
- Affected versionversion=6.4.2
- Affected versionversion=6.4.3
- Affected versionversion=6.5.1
- Affected versionversion=6.5.2
- Affected versionversion=6.5.25
- Affected versionversion=6.5.26
- Affected versionversion=6.5.28
- Affected versionversion=6.5.29
- Affected versionversion=6.5.3
- Affected versionversion=6.5.32
- Affected versionversion=6.5.33
- Affected versionversion=6.6.2
- Affected versionversion=6.6.25
- Affected versionversion=6.6.3
- Affected versionversion=6.6.4
- Affected versionversion=6.7.1
- Affected versionversion=6.7.2
- Affected versionversion=6.7.3
- Affected versionversion=6.7.4
- Affected versionversion=6.8.1
- Affected versionversion=6.8.2
- Affected versionversion=6.9.1
- Affected versionversion=6.9.2
- Affected versionversion=7.0.1
- Affected versionversion=7.0.12
- Affected versionversion=7.0.14
- Affected versionversion=7.0.2
- Affected versionversion=7.1.1
- Affected versionversion=7.1.15
- Affected versionversion=7.1.2
- Affected versionversion=7.1.3
- Affected versionversion=7.2.0
- Affected versionversion=7.2.1
- Affected versionversion=7.2.2
- Affected versionversion=7.3.1
- Affected versionversion=7.3.15
- Affected versionversion=7.3.2
- Affected versionversion=7.3.3
- Affected versionversion=7.3.5
- Affected versionversion=7.4.1
- Affected versionversion=7.4.2
- Affected versionversion=7.5.1
- Affected versionversion=7.5.2
- Affected versionversion=7.5.3
- Affected versionversion=7.5.4
- Affected versionversion=7.6.1
- Affected versionversion=7.6.2
- Affected versionversion=7.7.1
- Affected versionversion=7.7.2
- Affected versionversion=7.7.21
- Affected versionversion=7.8.1
- Affected versionversion=7.8.2
- Affected versionversion=7.9.1
- Affected versionversion=7.9.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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