CVE-2023-20266
Cisco Unity Connection 12.5\(1\)su6 … 14su3
Raw vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:NCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2023-20266 is a medium-severity Improper Verification of Cryptographic Signature (CWE-347) vulnerability in Cisco Unity Connection. Its CVSS base score is 6.5 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Junk Data (T1001.001); ranked at the 40th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-24445
Vulnerability Data
A vulnerability in Cisco Emergency Responder, Cisco Unified Communications Manager (Unified CM), Cisco Unified Communications Manager Session Management Edition (Unified CM SME), and Cisco Unity Connection could allow an authenticated, remote attacker to elevate privileges to root on an affected…
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device. This vulnerability exists because the application does not properly restrict the files that are being used for upgrades. An attacker could exploit this vulnerability by providing a crafted upgrade file. A successful exploit could allow the attacker to elevate privileges to root. To exploit this vulnerability, the attacker must have valid platform administrator credentials on an affected device.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 14 hardening rules · 5 OS baselines
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Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Policy addresses roles, responsibilities, and privilege management to prevent improper privilege assignments.
Access supervision ensures privileges are assigned and managed without improper escalation or retention.
Assigning group/role memberships and access authorizations (privileges) while reviewing accounts addresses improper privilege management.
Enforces proper privilege management by requiring all decisions through the verified reference monitor.
By mandating division of duties across roles, the control enforces proper privilege management and prevents a single entity from controlling an entire sensitive process.
Implements core proper privilege management by restricting to only required rights.
Policy requires training on privilege management and least privilege, making it harder to exploit improper privilege management weaknesses.
Training covers proper privilege management practices, making incorrect privilege assignments less likely.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Requires assessing authenticity and integrity of acquired assets, which commonly relies on signature verification but is limited to pre-acquisition.
Digital signatures are explicitly cited to protect integrity of data-at-rest, so proper verification directly mitigates the weakness.
Digital signatures are explicitly cited to protect integrity of data-in-transit, so proper verification directly mitigates the weakness.
Secure SDLC practices include code signing and signature verification requirements, addressing the weakness during development.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Defining and communicating authorization levels for each role limits the assignment of excessive or unnecessary privileges.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (higher-evidence rows only; rows rated `none` are excluded).
Oracle Linux 8 (2 rules)
- V-248574 YUM must be configured to prevent the installation of patches, service packs, device drivers, or OL 8 system components that have not been digitally signed using a certificate that is recognized and approved by the organization. blocks CWE-347
- V-248575 OL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. blocks CWE-347
Oracle Linux 9 (2 rules)
- V-271525 OL 9 must have GPG signature verification enabled for all software repositories. blocks CWE-347
- V-271523 OL 9 must check the GPG signature of locally installed software packages before installation. blocks CWE-347
RHEL 7 (2 rules)
- V-204447 The Red Hat Enterprise Linux operating system must prevent the installation of software, patches, service packs, device drivers, or operating system components from a repository without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. blocks CWE-347
- V-204448 The Red Hat Enterprise Linux operating system must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. blocks CWE-347
RHEL 8 (1 rule)
- V-230264 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components from a repository without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. blocks CWE-347
RHEL 9 (1 rule)
- V-257822 RHEL 9 must have GPG signature verification enabled for all software repositories. blocks CWE-347