SB20260912178 - Out-of-bounds write in Linux kernel ecryptfs

Description

This security bulletin contains information about 1 vulnerability.

1) Out-of-bounds write (CVE-ID: CVE-2026-89607)

CWE-ID: CWE-787 - Out-of-bounds write

CVSSv4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause memory corruption.

The vulnerability exists due to out-of-bounds writes in parse_tag_3_packet() and decrypt_passphrase_encrypted_session_key() when processing a crafted Tag 3 packet through the passphrase decryption path. A local user can supply a crafted Tag 3 packet with an oversized encrypted key size to cause memory corruption.

Only the AES-192 cipher configuration enables exploitation because its key size is set independently of the encrypted key size.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/14cb36a500a5a3afbc955dbf69dabc565f1a3b26
• https://git.kernel.org/stable/c/5babe9c177c364521e3e682b949c5a8c47f4a441
• https://git.kernel.org/stable/c/a419c9ebfc9a40ee56aaad6dc68bfd67d400817b
• https://git.kernel.org/stable/c/ccd13eff0e7356d2aa28b127b577e4e5ad4563f5