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CVE

CVE-2023-20135

A vulnerability in Cisco IOS XR Software image verification checks could allow an authenticated, local attacker to execu

A vulnerability in Cisco IOS XR Software image verification checks could allow an authenticated, local attacker to execute arbitrary code on the underlying operating system. This vulnerability is due to a time-of-check, time-of-use (TOCTOU) race condition when an install query regarding an ISO image is performed during an install operation that uses an ISO image. An attacker could exploit this vulnerability by modifying an ISO image and then carrying out install requests in parallel. A successful exploit could allow the attacker to execute arbitrary code on an affected device.

MEDIUM · CVSS 5.7 EPSS 0.00016
Monitor
  • No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-347Improper Verification of Cryptographic Signature
CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition
▤

Affected Products & Versions

2
cisco ios xr>= 7.5.2 and < 7.6
cisco ios xr>= 7.7 and < 7.10.1
▣

Scoring & Timeline

5.7
MEDIUM · CVSS v3.1 · psirt@cisco.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD13 Sep 2023 · 05:15 PM
CVSS VectorCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Technical impact
total
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

1
cisco-csafcisco-sa-lnt-L9zOkBz5
🔗

References & Sources

1
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-lnt-L9zOkBz5Vendor Advisory
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