SB2026051299 - Multiple vulnerabilities in Microsoft Windows Rich Text Edit

Description

This security bulletin contains information about 2 vulnerabilities.

1) Double free (CVE-ID: CVE-2026-21530)

CWE-ID: CWE-415 - Double Free

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to escalate privileges on the system.

The vulnerability exists due to a boundary error in Windows Rich Text Edit. A remote user can trick a victim to open a specially crafted file, win a race condition and gain elevated elevated privileges on the target system.

2) Double free (CVE-ID: CVE-2026-32170)

CWE-ID: CWE-415 - Double Free

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to escalate privileges on the system.

The vulnerability exists due to a boundary error in Windows Rich Text Edit. A remote user can trick a victim to open a specially crafted file, win a race condition and gain elevated elevated privileges on the target system.

Remediation

Install update from vendor's website.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21530
• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-32170