CVE-2026-89607ecryptfs: reject oversized encrypted_key_size in parse_tag_3_packet
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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]
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Received
- Record last updated
- Sep 14, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | 237fead619984cc48818fe12ee0ceada3f55b012 builds before 2cd21340163494d312836c77c9fbfe2530b3d075; from 237fead619984cc48818fe12ee0ceada3f55b012 before e2152d491ae62d96a32ed59778680a242af1fbc6; from 237fead619984cc48818fe12ee0ceada3f55b012 before d2802414081184f79a619ede178aeef3aa989793; 237fead619984cc48818fe12ee0ceada3f55b012 builds before 33e050cac841498b5175f0f385eee903fd98863c; from 237fead619984cc48818fe12ee0ceada3f55b012 before ccd13eff0e7356d2aa28b127b577e4e5ad4563f5; 237fead619984cc48818fe12ee0ceada3f55b012 builds before 14cb36a500a5a3afbc955dbf69dabc565f1a3b26; from 237fead619984cc48818fe12ee0ceada3f55b012 before a419c9ebfc9a40ee56aaad6dc68bfd67d400817b; 237fead619984cc48818fe12ee0ceada3f55b012 builds before 5babe9c177c364521e3e682b949c5a8c47f4a441 | CNA record |
References
- https://git.kernel.org/stable/c/2cd21340163494d312836c77c9fbfe2530b3d075
- https://git.kernel.org/stable/c/e2152d491ae62d96a32ed59778680a242af1fbc6
- https://git.kernel.org/stable/c/d2802414081184f79a619ede178aeef3aa989793
- https://git.kernel.org/stable/c/33e050cac841498b5175f0f385eee903fd98863c
- https://git.kernel.org/stable/c/ccd13eff0e7356d2aa28b127b577e4e5ad4563f5
- https://git.kernel.org/stable/c/14cb36a500a5a3afbc955dbf69dabc565f1a3b26
- https://git.kernel.org/stable/c/a419c9ebfc9a40ee56aaad6dc68bfd67d400817b
- https://git.kernel.org/stable/c/5babe9c177c364521e3e682b949c5a8c47f4a441
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.