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CVE-2026-89607

ecryptfs: reject oversized encrypted_key_size in parse_tag_3_packet

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, and 2 more
None on Exploit-DB, Metasploit or GitHub

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 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]

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • Linux Linux

    From 237fead619984cc48818fe12ee0ceada3f55b012 · fixed in 2cd21340163494d312836c77c9fbfe2530b3d075; From 237fead619984cc48818fe12ee0ceada3f55b012 · fixed in e2152d491ae62d96a32ed59778680a242af1fbc6; From 237fead619984cc48818fe12ee0ceada3f55b012 · fixed in d2802414081184f79a619ede178aeef3aa989793; From 237fead619984cc48818fe12ee0ceada3f55b012 · fixed in 33e050cac841498b5175f0f385eee903fd98863c; From 237fead619984cc48818fe12ee0ceada3f55b012 · fixed in ccd13eff0e7356d2aa28b127b577e4e5ad4563f5; From 237fead619984cc48818fe12ee0ceada3f55b012 · fixed in 14cb36a500a5a3afbc955dbf69dabc565f1a3b26; From 237fead619984cc48818fe12ee0ceada3f55b012 · fixed in a419c9ebfc9a40ee56aaad6dc68bfd67d400817b; From 237fead619984cc48818fe12ee0ceada3f55b012 · fixed in 5babe9c177c364521e3e682b949c5a8c47f4a441

  • Linux Linux

    2.6.19

  • KernelLinux

    From 2.6.19 · fixed in 5.10.270; From 5.11.0 · fixed in 5.15.221; From 5.16.0 · fixed in 6.1.188; From 6.2.0 · fixed in 6.6.157; From 6.7.0 · fixed in 6.12.109; From 6.13.0 · fixed in 6.18.50; From 6.19.0 · fixed in 7.2.4

References 8

git.kernel.org