Business

Cisco warns zero-day vulnerability exploited in attacks on IOS software

By Sead Fadilpašić

Copyright techradar

Cisco warns zero-day vulnerability exploited in attacks on IOS software

Skip to main content

Tech Radar Pro

Tech Radar Gaming

Close main menu

the business technology experts

België (Nederlands)

Deutschland

North America

US (English)

Australasia

New Zealand

View Profile

Search TechRadar

Expert Insights

Website builders

Web hosting

Best web hosting
Best office chairs
Best website builder
Best antivirus
Expert Insights

Don’t miss these

Cisco ISE maximum severity flaw lets hackers execute root code

FBI warns Russian hackers are targeting an old Cisco security flaw, so patch now

Citrix patches a trio of high-severity security bugs, so be on your guard

Cisco warns of worrying major security flaw in firewall command center, so patch now

Cisco warns of a serious security flaw in comms platform – and that it needs patching immediately

HPE warns hardcoded passwords in Aruba hardware could pose a major security risk

CISA warns hackers are actively exploiting critical CitrixBleed 2

WatchGuard warns users Firebox firewalls may have a critical issue – here’s what we know

CISA flags some more serious Ivanti software flaws, so patch now

CitrixBleed 2 exploits are now in the wild, so patch now

CitrixBleed 2 flaws are officially here – so get patching or leave your systems at risk

Microsoft releases urgent SharePoint security flaw patches – here’s what you need to know, and how to update

Mitel warns critical security flaw could let hackers completely bypass logins

Trend Micro tells users to patch immediately to protect from Apex One zero-day

Hacker using backdoor to exploit SonicWall Secure Mobile Access to steal credentials

Cisco warns zero-day vulnerability exploited in attacks on IOS software

Sead Fadilpašić

25 September 2025

A patch is already available, so update now

When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works.

(Image credit: Shutterstock / Valriya Zankovych)

Cisco patches CVE-2025-20352, a high-severity SNMP flaw actively exploited in the wild
Attackers can cause DoS or gain root access using crafted SNMP packets and credentials
No workaround exists; users must apply Cisco’s patch or use temporary mitigation steps

Cisco has patched a high-severity vulnerability in its IOS and IOS XE Software it says is being actively exploited in the wild.

In a recently published security advisory, the company said it discovered, and fixed, a stack overflow condition in the Simple Network Management Protocol (SNMP) subsystem of the OS. It is tracked as CVE-2025-20352, and has a severity score of 7.7/10 (high).
Successfully exploiting the bug could grant low-privileged attackers the ability to reload the systems and cause a DoS condition. A high-privileged attacker, on the other hand, could use the bug to run arbitrary code as the root user, and fully take over the compromised endpoints.

You may like

Cisco ISE maximum severity flaw lets hackers execute root code

FBI warns Russian hackers are targeting an old Cisco security flaw, so patch now

Citrix patches a trio of high-severity security bugs, so be on your guard

Patches and mitigations
To cause the DoS, the attacker must have the SNMPv2c or earlier read-only community string or valid SNMPv3 user credentials, the networking giant explained.

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. The flaw could be exploited through a custom SNMP packet sent over IPv4 or IPv6.
All devices running a vulnerable release of IOS and IOS XE are affected, the company stressed, adding that all older versions of SNMP were flawed. This includes Meraki MS390 and Cisco Catalyst 9300 Series Switches that are running Meraki CS 17, as well.
To address the vulnerability, Cisco released a patch, and warned the users to apply it immediately since the bug is being actively abused in the wild: “The Cisco Product Security Incident Response Team (PSIRT) became aware of successful exploitation of this vulnerability in the wild after local Administrator credentials were compromised,” the company said.

Are you a pro? Subscribe to our newsletter
Sign up to the TechRadar Pro newsletter to get all the top news, opinion, features and guidance your business needs to succeed!
Contact me with news and offers from other Future brandsReceive email from us on behalf of our trusted partners or sponsorsBy submitting your information you agree to the Terms & Conditions and Privacy Policy and are aged 16 or over.
There are no workarounds to address the flaw, but there is a mitigation that can be used as a temporary solution until the patch is deployed. More details about the mitigation can be found on this link.
Via BleepingComputer
You might also like

Cisco patches critical security issues, so update now
Take a look at our guide to the best authenticator app
We’ve rounded up the best password managers

Sead Fadilpašić

Social Links Navigation

Sead is a seasoned freelance journalist based in Sarajevo, Bosnia and Herzegovina. He writes about IT (cloud, IoT, 5G, VPN) and cybersecurity (ransomware, data breaches, laws and regulations). In his career, spanning more than a decade, he’s written for numerous media outlets, including Al Jazeera Balkans. He’s also held several modules on content writing for Represent Communications.

You must confirm your public display name before commenting

Please logout and then login again, you will then be prompted to enter your display name.

Cisco ISE maximum severity flaw lets hackers execute root code

FBI warns Russian hackers are targeting an old Cisco security flaw, so patch now

Citrix patches a trio of high-severity security bugs, so be on your guard

Cisco warns of worrying major security flaw in firewall command center, so patch now

Cisco warns of a serious security flaw in comms platform – and that it needs patching immediately

HPE warns hardcoded passwords in Aruba hardware could pose a major security risk

Latest in Security

Jaguar Land Rover facing costs of “millions per week” following cyberattack – due to a lack of insurance cover

Python developers targeted with new password-stealing phishing attacks – here’s how to stay safe

Libraseva urges users to patch now as it issues emergency fix following attacks

GitHub is finally tightening up security around npm following multiple attacks

Cloudflare says it has (once again) blocked the largest-ever DDoS attack in history

Watch out – even small businesses are now facing threats from deepfake attacks

Latest in News

Microsoft Flight Simulator 2024 is flying onto PS5 in December, with PSVR 2 support coming in 2026

PlayStation reveals Pulse Elevate speakers designed for PS5 and PC – and they have a pretty weird feature set

Sony announces new release date for Spider-Man: Beyond the Spider-Verse – and it’s a move that’s baffled me

It may have leaked early, but Forza Horizon 6’s first trailer confirms Japan setting and a 2026 release

Hoping for some big Black Friday laptop deals? Intel CPU price hikes could scupper your plans

YouTube is finally letting you hide one of its most annoying features – and you’re going to be thankful for this

LATEST ARTICLES

Quordle hints and answers for Friday, September 26 (game #1341)

NYT Connections hints and answers for Friday, September 26 (game #838)

NYT Strands hints and answers for Friday, September 26 (game #572)

PlayStation reveals Pulse Elevate speakers designed for PS5 and PC – and they have a pretty weird feature set

Microsoft Flight Simulator 2024 is flying onto PS5 in December, with PSVR 2 support coming in 2026

TechRadar is part of Future US Inc, an international media group and leading digital publisher. Visit our corporate site.

Contact Future’s experts

Terms and conditions

Privacy policy

Cookies policy

Advertise with us

Web notifications

Accessibility Statement

Future US, Inc. Full 7th Floor, 130 West 42nd Street,

Please login or signup to comment

Please wait…