Out-of-bounds write in OpenSSL - CVE-2026-63072
Published: August 26, 2026
Vulnerability identifier: #VU145417
CSH Severity: Medium
CVSS v4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-63072
CWE-ID: CWE-787
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to out-of-bounds write in OpenSSL CMS decryption key unwrapping logic when decrypting a crafted CMS message through CMS_decrypt(). A remote attacker can supply a crafted CMS message to cause a denial of service.
The issue causes a deterministic 8-byte heap write immediately past the allocation when the key-wrap OID is changed to select the padded variant.
Affected software
OpenSSL
Debian Linux
FreeBSD
openssl (Debian package)
Debian Linux
FreeBSD
openssl (Debian package)
How to mitigate CVE-2026-63072
Install security update from vendor's website.
OpenSSL - addressed in versions 1.1.1zi, 3.0.22, 3.4.7, 3.5.8, 3.6.4, 4.0.2
openssl (Debian package) - update to 3.5.7-1~deb13u2
openssl (Debian package) - update to 3.5.7-1~deb13u2