CVE-2025-20352
A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco IOS Software and Cisco IOS XE Software could allow the following: An…
- Severity
- 7.7 / 10
- High · CVSS 3.1
- Exploit chance (EPSS)
- 41.50%
- Chance of exploitation in the next 30 days. Higher than 98.68% of scored vulnerabilities.
- Known exploited
- Yes
- In CISA's catalog since Sep 29, 2025
- Weakness
- CWE-121 Stack-based Buffer Overflow
- Fix
- None yet
- No fixed version published
Description
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 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.
How to fix
No fixed version has been published yet. Until one is, remove or replace the package, or turn off or isolate the affected feature. This page updates when a fix ships.
Severity breakdown
CVSS 3.1 7.7
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Changed
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Weakness
CWE-121: Stack-based Buffer Overflow
A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).
How to prevent it
- Operation, Build and Compilation: Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.
- Architecture and Design: Use an abstraction library to abstract away risky APIs. Not a complete solution.
- Implementation: Implement and perform bounds checking on input.
- Implementation: Do not use dangerous functions such as gets. Use safer, equivalent functions which check for boundary errors.
- Operation, Build and Compilation: Run or compile the software using features or extensions that randomly arrange the positions of a program's executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code. Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as "rebasing" (for Windows) and "prelinking" (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking. For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].
References
Advisories
Other links
Timeline
- Published
- Added to CISA's Known Exploited Vulnerabilities catalog
- Remediation due for U.S. federal agencies
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| CVE-2021-27137 An issue was discovered in router/upnp/src/ssdp.c in DD-WRT before 45724. | High Known exploited | Same weakness, CWE-121 |
| GHSA-mmjf-rqrv-855v Microsoft Security Advisory CVE-2026-50527 – .NET Denial of Service Vulnerability | High | Same weakness, CWE-121 |
| GHSA-3v45-f3vh-wg7m Oj: Stack Buffer Overflow in Oj.dump via Large Indent | High | Same weakness, CWE-121 |
| CVE-2026-7273 A stack-based buffer overflow vulnerability in the CGI program of Zyxel GS1900-48HPv2 firmware versions through 2.90(ABTQ.1)C0 could allow a LAN-based,… | High Known exploited | Same weakness, CWE-121 |
| GHSA-ghm9-cr32-g9qj rust-openssl: rustMdCtxRef::digest_final() writes past caller buffer with no length check | High | Same weakness, CWE-121 |
| GHSA-98cp-rj9f-6v5g ImageMagick has has a stack-buffer-overflow in MNG encoder with oversized pallete | Medium | Same weakness, CWE-121 |
| GHSA-6588-8gv4-xfgh Microsoft Security Advisory CVE-2026-32203 – .NET and Visual Studio Denial of Service Vulnerability | High | Same weakness, CWE-121 |
| GHSA-8793-7xv6-82cf ImageMagick has an Out-of-bounds Write via InterpretImageFilename | Medium | Same weakness, CWE-121 |
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