CVE-2021-21811

Name: CVE-2021-21811
Creator: NVD / NIST
Published: 2021-08-31T17:15:07.613+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 1.14%

Last modified Jun 17, 2026

CVE-2021-21811 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. A memory corruption vulnerability exists in the XML-parsing CreateLabelOrAttrib functionality of AT&T Labs’ Xmill 0.7. A specially crafted XML file can lead to a heap buffer overflow. EPSS estimates a 1.14% chance of exploitation in the next 30 days.

Description

A memory corruption vulnerability exists in the XML-parsing CreateLabelOrAttrib functionality of AT&T Labs’ Xmill 0.7. A specially crafted XML file can lead to a heap buffer overflow. An attacker can provide a malicious file to trigger this vulnerability.

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

1.14%

62.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Att	Xmill	0.7

References

https://talosintelligence.com/vulnerability_reports/TALOS-2021-1279Exploit, Third Party Advisory
https://talosintelligence.com/vulnerability_reports/TALOS-2021-1279Exploit, Third Party Advisory

Timeline

Published: Aug 31, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-21811?

How severe is CVE-2021-21811?

CVE-2021-21811 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 1.14% probability of exploitation in the next 30 days.

How do I fix CVE-2021-21811?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-21811?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST