CVE-2023-20135
A vulnerability in Cisco IOS XR Software image verification checks could allow an authenticated,...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- High
- Privileges needed
- High
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
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.
- Record
CVE-2023-20135- CVSS 3.1
- 5.7 Medium
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-347
- Updated
- 2026-11-02
EUVDEUVD-2023-24314
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.
- Record
EUVD-2023-24314- CVSS 3.1
- 5.7 Medium
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-6v48-qpg5-fj4m
A vulnerability in Cisco IOS XR Software image verification checks could allow an authenticated,...
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.
- Record
GHSA-6v48-qpg5-fj4m- CVSS 3.1
- 5.7 Medium
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-347, CWE-367
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2023-20135- CVSS 3.1
- 5.7 Medium
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N - CVSS 3.1
- 7.0 High
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-347, CWE-367
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2023-20135 is a medium vulnerability (CVSS 5.7) in Cisco Ios Xr Software, published September 13, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.09%, the 0th percentile. No source names a fixed version.