---
id: CVE-2026-89607
title: 'ecryptfs: reject oversized encrypted_key_size in parse_tag_3_packet'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ecryptfs: reject oversized encrypted_key_size in parse_tag_3_packet

  parse_tag_3_packet() set encrypted_key_size from the Tag 3 packet body
  without bounding it against …
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-787
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 237fead619984cc48818fe12ee0ceada3f55b012 <
    2cd21340163494d312836c77c9fbfe2530b3d075
  - >-
    Linux >= 237fead619984cc48818fe12ee0ceada3f55b012 <
    e2152d491ae62d96a32ed59778680a242af1fbc6
  - >-
    Linux >= 237fead619984cc48818fe12ee0ceada3f55b012 <
    d2802414081184f79a619ede178aeef3aa989793
  - >-
    Linux >= 237fead619984cc48818fe12ee0ceada3f55b012 <
    33e050cac841498b5175f0f385eee903fd98863c
  - >-
    Linux >= 237fead619984cc48818fe12ee0ceada3f55b012 <
    ccd13eff0e7356d2aa28b127b577e4e5ad4563f5
  - >-
    Linux >= 237fead619984cc48818fe12ee0ceada3f55b012 <
    14cb36a500a5a3afbc955dbf69dabc565f1a3b26
  - >-
    Linux >= 237fead619984cc48818fe12ee0ceada3f55b012 <
    a419c9ebfc9a40ee56aaad6dc68bfd67d400817b
  - >-
    Linux >= 237fead619984cc48818fe12ee0ceada3f55b012 <
    5babe9c177c364521e3e682b949c5a8c47f4a441
  - Linux 2.6.19
published: '2026-09-11'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T08:49:39.398Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-89607'
references:
  - url: 'https://git.kernel.org/stable/c/2cd21340163494d312836c77c9fbfe2530b3d075'
  - url: 'https://git.kernel.org/stable/c/e2152d491ae62d96a32ed59778680a242af1fbc6'
  - url: 'https://git.kernel.org/stable/c/d2802414081184f79a619ede178aeef3aa989793'
  - url: 'https://git.kernel.org/stable/c/33e050cac841498b5175f0f385eee903fd98863c'
  - url: 'https://git.kernel.org/stable/c/ccd13eff0e7356d2aa28b127b577e4e5ad4563f5'
  - url: 'https://git.kernel.org/stable/c/14cb36a500a5a3afbc955dbf69dabc565f1a3b26'
  - url: 'https://git.kernel.org/stable/c/a419c9ebfc9a40ee56aaad6dc68bfd67d400817b'
  - url: 'https://git.kernel.org/stable/c/5babe9c177c364521e3e682b949c5a8c47f4a441'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89607.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89607'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532523'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89607'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89607'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89607.mbox
tags:
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00169
epssPercentile: 0.06191
scores:
  cna: 7.8
  vendor: 7
ingestedAt: '2026-09-14T15:23:07.451Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

ecryptfs: reject oversized encrypted_key_size in parse_tag_3_packet

parse_tag_3_packet() set encrypted_key_size from the Tag 3 packet body
without bounding it against ECRYPTFS_MAX_KEY_BYTES (64). When
encrypted_key_size > 64, decrypt_passphrase_encrypted_session_key()
sets decrypted_key_size = encrypted_key_size and performs two
out-of-bounds writes:

1. crypto_skcipher_decrypt() writes encrypted_key_size bytes into
   decrypted_key[64] via scatterlist, overflowing into the parent
   ecryptfs_auth_tok struct.
2. memcpy(crypt_stat->key, decrypted_key, decrypted_key_size) writes
   into crypt_stat->key[64], corrupting root_iv, keysig_list, and
   mutexes in ecryptfs_crypt_stat.

Only AES-192 (cipher code 0x08) enables this because it sets
crypt_stat->key_size = 24 independently of encrypted_key_size,
allowing crypto_skcipher_setkey() to succeed while encrypted_key_size
exceeds ECRYPTFS_MAX_KEY_BYTES.

The PKI decryption path (parse_tag_65_packet) already validates
decrypted_key_size <= ECRYPTFS_MAX_KEY_BYTES; the passphrase path
omits this check.

Bound encrypted_key_size against ECRYPTFS_MAX_KEY_BYTES (64) rather
than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES (512). The 64-byte limit also
protects the 512-byte encrypted_key[] buffer, so the former 512-byte
check is removed as redundant.

[tyhicks: Adjust the code comment to refer to macros representing the
 buffer sizes rather than mentioning the buffer size values since they
 may change in the future]

## Affected

- `Linux >= 237fead619984cc48818fe12ee0ceada3f55b012 < 2cd21340163494d312836c77c9fbfe2530b3d075`
- `Linux >= 237fead619984cc48818fe12ee0ceada3f55b012 < e2152d491ae62d96a32ed59778680a242af1fbc6`
- `Linux >= 237fead619984cc48818fe12ee0ceada3f55b012 < d2802414081184f79a619ede178aeef3aa989793`
- `Linux >= 237fead619984cc48818fe12ee0ceada3f55b012 < 33e050cac841498b5175f0f385eee903fd98863c`
- `Linux >= 237fead619984cc48818fe12ee0ceada3f55b012 < ccd13eff0e7356d2aa28b127b577e4e5ad4563f5`
- `Linux >= 237fead619984cc48818fe12ee0ceada3f55b012 < 14cb36a500a5a3afbc955dbf69dabc565f1a3b26`
- `Linux >= 237fead619984cc48818fe12ee0ceada3f55b012 < a419c9ebfc9a40ee56aaad6dc68bfd67d400817b`
- `Linux >= 237fead619984cc48818fe12ee0ceada3f55b012 < 5babe9c177c364521e3e682b949c5a8c47f4a441`
- `Linux 2.6.19`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 6 · updated 2026-09-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89607.json)