CVE-2025-67187: A stack-based buffer overflow vulnerability was identified in TOTOLINK A950RG V4.1.2cu.5204_B20210112

This week

CRITICAL 9.8REMOTEMITIGATE

CVE-2025-67187 is a critical-severity flaw (CVSS 9.8) affecting a950rg firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A stack-based buffer overflow vulnerability was identified in TOTOLINK A950RG V4.1.2cu.5204_B20210112. The flaw exists in the setIpQosRules interface of /lib/cste_modules/firewall.so where the comment parameter is not properly validated for length.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 57%)
CISA exploited list	No
Weakness	CWE-121
Published	2026-02-03
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: totolink

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-02-03 18:16 UTCPublished CVE record published
2026-06-17 09:57 UTCUpdated Record last modified

totolink a950rg firmware MITIGATE

Affected: 4.1.2cu.5204_b20210112

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.1.2cu.5204_b20210112

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

Fedora 46 · php-pecl-yac · FIXED · 3.0.2-1.fc46 · FEDORA-2026-0322a78385 · source

sudo dnf upgrade --advisory=FEDORA-2026-0322a78385

Fedora ELN · openldap · FIXED · 2.6.16-1.eln159 · FEDORA-2026-4b30c86326 · source

sudo dnf upgrade --advisory=FEDORA-2026-4b30c86326

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Write-up: github.com/SunnyYANGyaya/cuicuishark-sheep-fishIOT/blob/main/ToTolink/A950RG/5024-setIpQos

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-67187?

a950rg firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2025-67187 being exploited?

CVE-2025-67187 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-67187 affect?

CVE-2025-67187 affects a950rg firmware. Severity is critical (CVSS 9.8). A stack-based buffer overflow vulnerability was identified in TOTOLINK A950RG V4.1.2cu.5204_B20210112. The flaw exists in the setIpQosRules interface of /lib/cste_modules/firewall.so where the comment parameter is not properly validated for

How urgent is CVE-2025-67187?

Priority 55/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

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References

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