CVE-2025-28020Public exploitNetwork attack vector

Unauthenticated memory corruption via unchecked v25 copy

Published Apr 23, 2025 · Updated Apr 24, 2025

Buffer overflow in TOTOLINK A800R firmware 4.1.2cu.5137_B20200730 allows remote attackers to corrupt memory through the v25 parameter. The downloadFile.cgi handler copies attacker-controlled v25 input into a fixed-size destination without verifying that the input fits. No authentication or user interaction is required; a successful request corrupts process memory, while code execution has not been established.

CVSS severity7.3
High
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Buffer overflow in TOTOLINK A800R firmware 4.1.2cu.5137_B20200730 allows remote attackers to corrupt memory through the v25 parameter. The downloadFile.cgi handler copies attacker-controlled v25 input into a fixed-size destination without verifying that the input fits. No authentication or user interaction is required; a successful request corrupts process memory, while code execution has not been established.

The record

CVE
CVE-2025-28020
Published
Apr 23, 2025
Updated
Apr 24, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 23, 2025CVE publishedPublication date reported by the CVE source.
  2. Apr 24, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo