CVE-2026-89606: ecryptfs: reject too-small tag 70 packets
In the Linux kernel, the following vulnerability has been resolved:
ecryptfs: reject too-small tag 70 packets
ecryptfsparsetag70packet() subtracts fixed metadata fields from the parsed packet body size to derive the encrypted filename size. A malformed packet with a body smaller than those fixed fields can underflow that size calculation.
Reject tag 70 packets before the subtraction unless the body contains the signature, cipher code, and at least one byte of encrypted filename data.
Affected Software
Event History
Frequently Asked Questions
What condition triggers the vulnerable size calculation?
The issue is triggered when ecryptfs parses a malformed tag 70 packet whose body is smaller than the fixed metadata fields. Subtracting those fields to calculate the encrypted filename size can then underflow.
What packet contents are required after the fix?
Tag 70 packets must contain a signature, a cipher code, and at least one byte of encrypted filename data. Packets that do not meet that minimum body size are rejected before the size subtraction.