CVE-2021-26727: Multiple command injections and stack-based buffer overflows vulnerabilities in the SubNet_handler_func functi

This week

CRITICAL 10.0REMOTEMITIGATE

CVE-2021-26727 is a critical-severity flaw (CVSS 10.0) affecting iac-ast2500a firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Multiple command injections and stack-based buffer overflows vulnerabilities in the SubNet_handler_func function of spx_restservice allow an attacker to execute arbitrary code with the same privileges as the server user (root). This issue affects: Lanner Inc IAC-AST2500A standard firmware version 1.10.0.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	10.0 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.7% (top 14%)
CISA exploited list	No
Weakness	CWE-94, CWE-121, CWE-77, CWE-787
Published	2022-10-24
Last modified	2026-06-17

Publisher (CNA): Nozomi Networks Inc. · Vendor: lannerinc

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

Am I affected?

Timeline

2022-10-24 14:15 UTCPublished CVE record published
2026-06-17 03:43 UTCUpdated Record last modified

lannerinc iac-ast2500a firmware MITIGATE

Affected: 1.10.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.10.0

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-2021-26727?

iac-ast2500a firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-26727 being exploited?

CVE-2021-26727 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-2021-26727 affect?

CVE-2021-26727 affects iac-ast2500a firmware. Severity is critical (CVSS 10.0). Multiple command injections and stack-based buffer overflows vulnerabilities in the SubNet_handler_func function of spx_restservice allow an attacker to execute arbitrary code with the same privileges as the server user (root). This issue a

How urgent is CVE-2021-26727?

Priority 61/100. Critical severity; Remotely exploitable, no login, no user action

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References

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