CVE-2025-20352
Memory Safety in Cisco Ios 12.2\(33\)sxi … 15.9\(3\)m9
Raw vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:HSummary
CVE-2025-20352 is a high-severity Stack-based Buffer Overflow (CWE-121) vulnerability in Cisco Ios. Its CVSS base score is 7.7 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 2% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
A stack overflow vulnerability exists in the SNMP subsystem of Cisco IOS Software and Cisco IOS XE Software, affecting all SNMP versions. The flaw resides in how the software processes SNMP packets and can be triggered over IPv4 or IPv6.
An authenticated remote attacker possessing the SNMPv2c or earlier read-only community string or valid SNMPv3 credentials can send a crafted packet to trigger a denial-of-service reload. On IOS XE devices, an attacker who additionally holds administrative or privilege-15 credentials can leverage the same vector to execute arbitrary code as root and gain full control of the device.
The vulnerability is tracked in the CISA Known Exploited Vulnerabilities catalog, and Cisco has published an advisory at sec.cloudapps.cisco.com. Its EPSS score rose from a low baseline to a peak of 0.0420, indicating emerging exploitation interest after disclosure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-31023
Vulnerability Data
A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco IOS Software and Cisco IOS XE Software could allow the following: An authenticated, remote attacker with low privileges could cause a denial of service (DoS) condition on an…
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affected device that is running Cisco IOS Software or Cisco IOS XE Software. To cause the DoS, the attacker must have the SNMPv2c or earlier read-only community string or valid SNMPv3 user credentials. An authenticated, remote attacker with high privileges could execute code as the root user on an affected device that is running Cisco IOS XE Software. To execute code as the root user, the attacker must have the SNMPv1 or v2c read-only community string or valid SNMPv3 user credentials and administrative or privilege 15 credentials on the affected device. An attacker could exploit this vulnerability by sending a crafted SNMP packet to an affected device over IPv4 or IPv6 networks. This vulnerability is due to a stack overflow condition in the SNMP subsystem of the affected software. A successful exploit could allow a low-privileged attacker to cause the affected system to reload, resulting in a DoS condition, or allow a high-privileged attacker to execute arbitrary code as the root user and obtain full control of the affected system. Note: This vulnerability affects all versions of SNMP.
- CWE(s)
- KEV Date Added
- 29 September 2025
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 2 hardening rules · 2 OS baselines
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Mitigating Controls (NIST 800-53 r5) AI
Developer testing and analysis can discover stack-buffer overflows before deployment.
Input validation directly stops untrusted data from exceeding stack buffer bounds.
Memory-protection mechanisms limit the ability to execute injected code after a stack overflow.
Secure-engineering principles include bounds-checked coding and safe buffer handling that avoid introducing the flaw.
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.
Secure-development practices directly prevent introduction of stack buffer overflows.
Vulnerability scanning can discover stack buffer overflows but does not prevent their introduction.
Patching eliminates known instances of the weakness after discovery.
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.
Security testing (fuzzing, static analysis) detects stack overflows before release.
Secure SDLC mandates buffer-safety practices that directly prevent stack overflows.
Application security requirements can specify buffer-size and input-validation rules.
Secure architecture principles include memory-safety and least-privilege stack usage.
Secure coding standards explicitly forbid unsafe buffer handling that causes CWE-121.
Change-management gates can enforce security reviews that catch buffer issues.
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` (authoritative rows only; rows rated `none` are excluded).
Oracle Linux 8 (1 rule)
- V-248594 OL 8 must implement address space layout randomization (ASLR) to protect its memory from unauthorized code execution. prevents CWE-121
Oracle Linux 9 (1 rule)
- V-271452 OL 9 must use a Linux Security Module configured to enforce limits on system services. prevents CWE-121