CVE-2021-45757: ASUS AC68U <=3.0.0.4.385.20852 is affected by a buffer overflow in blocking.cgi, which may cause a denial of s

Q: How do I fix CVE-2021-45757?

rt-ac68u firmware: upgrade to newer than 3.0.0.4.385.20852. Exact commands for each OS are on this page.

Q: Is CVE-2021-45757 being exploited?

CVE-2021-45757 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-45757 affect?

CVE-2021-45757 affects rt-ac68u firmware. Severity is high (CVSS 7.5). ASUS AC68U <=3.0.0.4.385.20852 is affected by a buffer overflow in blocking.cgi, which may cause a denial of service (DoS).

Q: How urgent is CVE-2021-45757?

Priority 53/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

HIGH 7.5REMOTEUPGRADE

CVE-2021-45757 is a high-severity flaw (CVSS 7.5) affecting rt-ac68u firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

ASUS AC68U <=3.0.0.4.385.20852 is affected by a buffer overflow in blocking.cgi, which may cause a denial of service (DoS).

Why this priority

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

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.1% (top 35%)
CISA exploited list	No
Weakness	CWE-120
Published	2022-03-23
Last modified	2026-07-09

Publisher (CNA): MITRE · Vendor: asus

Last updated 2026-07-09 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2022-03-23 11:15 UTCPublished CVE record published
2026-07-09 01:17 UTCUpdated Record last modified

asus rt-ac68u firmware UPGRADE

Affected: <= 3.0.0.4.385.20852

Fixed in: newer than 3.0.0.4.385.20852

Safe to downgrade to: no unaffected older release

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.

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-2021-45757?

rt-ac68u firmware: upgrade to newer than 3.0.0.4.385.20852. Exact commands for each OS are on this page.

Is CVE-2021-45757 being exploited?

CVE-2021-45757 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-2021-45757 affect?

CVE-2021-45757 affects rt-ac68u firmware. Severity is high (CVSS 7.5). ASUS AC68U <=3.0.0.4.385.20852 is affected by a buffer overflow in blocking.cgi, which may cause a denial of service (DoS).

How urgent is CVE-2021-45757?

Priority 53/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2021-45756 CRITICAL 9.8 UPGRADE UPGRADE Asus RT-AC68U <3.0.0.4.385.20633 and RT-AC5300 <3.0.0.4.384.82072 are affected by a buffer overflow in blockin
CVE-2021-37317 CRITICAL 9.1 UPGRADE Directory Traversal vulnerability in Cloud Disk in ASUS RT-AC68U router firmware version before 3.0.0.4.386.41
CVE-2021-37316 HIGH 7.5 UPGRADE SQL injection vulnerability in Cloud Disk in ASUS RT-AC68U router firmware version before 3.0.0.4.386.41634 al
CVE-2021-37315 CRITICAL 9.1 UPGRADE Incorrect Access Control issue discoverd in Cloud Disk in ASUS RT-AC68U router firmware version before 3.0.0.4
CVE-2018-9285 CRITICAL 9.8 UPGRADE UPGRADE Main_Analysis_Content.asp in /apply.cgi on ASUS RT-AC66U, RT-AC68U, RT-AC86U, RT-AC88U, RT-AC1900, RT-AC2900,

References

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