CVE-2026-89607

HIGHCVSS 7.8/10EPSS 0.16%

Last modified

CVE-2026-89607 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. 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. EPSS estimates a 0.16% chance of exploitation in the next 30 days.

Description

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]

Metrics

EPSS Probability
0.16%

5.8th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 237fead619984cc48818fe12ee0ceada3f55b012, < 2cd21340163494d312836c77c9fbfe2530b3d075; >= 237fead619984cc48818fe12ee0ceada3f55b012, < e2152d491ae62d96a32ed59778680a242af1fbc6; >= 237fead619984cc48818fe12ee0ceada3f55b012, < d2802414081184f79a619ede178aeef3aa989793; >= 237fead619984cc48818fe12ee0ceada3f55b012, < 33e050cac841498b5175f0f385eee903fd98863c; >= 237fead619984cc48818fe12ee0ceada3f55b012, < ccd13eff0e7356d2aa28b127b577e4e5ad4563f5; >= 237fead619984cc48818fe12ee0ceada3f55b012, < 14cb36a500a5a3afbc955dbf69dabc565f1a3b26; >= 237fead619984cc48818fe12ee0ceada3f55b012, < a419c9ebfc9a40ee56aaad6dc68bfd67d400817b; >= 237fead619984cc48818fe12ee0ceada3f55b012, < 5babe9c177c364521e3e682b949c5a8c47f4a441
LinuxLinux2.6.19

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-89607?
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]
How severe is CVE-2026-89607?
CVE-2026-89607 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.16% probability of exploitation in the next 30 days.
How do I fix CVE-2026-89607?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST