{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-89607","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-11T19:38:34.733Z","datePublished":"2026-09-11T19:45:09.583Z","dateUpdated":"2026-09-14T12:01:27.820Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-14T12:01:27.820Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\necryptfs: reject oversized encrypted_key_size in parse_tag_3_packet\n\nparse_tag_3_packet() set encrypted_key_size from the Tag 3 packet body\nwithout bounding it against ECRYPTFS_MAX_KEY_BYTES (64). When\nencrypted_key_size > 64, decrypt_passphrase_encrypted_session_key()\nsets decrypted_key_size = encrypted_key_size and performs two\nout-of-bounds writes:\n\n1. crypto_skcipher_decrypt() writes encrypted_key_size bytes into\n   decrypted_key[64] via scatterlist, overflowing into the parent\n   ecryptfs_auth_tok struct.\n2. memcpy(crypt_stat->key, decrypted_key, decrypted_key_size) writes\n   into crypt_stat->key[64], corrupting root_iv, keysig_list, and\n   mutexes in ecryptfs_crypt_stat.\n\nOnly AES-192 (cipher code 0x08) enables this because it sets\ncrypt_stat->key_size = 24 independently of encrypted_key_size,\nallowing crypto_skcipher_setkey() to succeed while encrypted_key_size\nexceeds ECRYPTFS_MAX_KEY_BYTES.\n\nThe PKI decryption path (parse_tag_65_packet) already validates\ndecrypted_key_size <= ECRYPTFS_MAX_KEY_BYTES; the passphrase path\nomits this check.\n\nBound encrypted_key_size against ECRYPTFS_MAX_KEY_BYTES (64) rather\nthan ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES (512). The 64-byte limit also\nprotects the 512-byte encrypted_key[] buffer, so the former 512-byte\ncheck is removed as redundant.\n\n[tyhicks: Adjust the code comment to refer to macros representing the\n buffer sizes rather than mentioning the buffer size values since they\n may change in the future]"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - Triggered by a local open/setattr on an eCryptfs mount: ecryptfs_open -> read_or_initialize_metadata -> ecryptfs_read_metadata parses attacker-supplied Tag 3 packets from the lower file header (or xattr). The kernel does not process this as network protocol data.\nAC:L - The attacker fully controls the Tag 3 body, including AES-192 cipher code 0x08 and an AES-block-aligned encrypted_key_size of 80-512 bytes. decrypt_passphrase_encrypted_session_key() then overflows deterministically; no race or uninfluenced memory layout is required to trigger the writes.\nPR:L - An unprivileged user reaches this on standard eCryptfs deployments (setuid-root mount.ecryptfs_private and per-user encrypted home/Private). They plant a crafted lower file under their own .Private directory and open it through the already-mounted eCryptfs tree; init-namespace root is not required.\nUI:N - The attacker performs the whole sequence themselves: install a matching passphrase auth token, write the malformed Tag 3/Tag 11 header into their lower directory, and open the file. No action by another user is required.\nS:U - The out-of-bounds writes corrupt kernel heap and eCryptfs inode-private objects in the same kernel security authority. This is local privilege escalation, not a VM, IOMMU, or sandbox boundary crossing.\nC:H - crypto_skcipher_decrypt() and memcpy() write tens to hundreds of bytes past decrypted_key[64] and crypt_stat->key[64], overflowing into reserved/token fields, keysig_list, mutexes, and adjacent slab/inode-cache objects. That heap corruption can be groomed into an arbitrary kernel read.\nI:H - Session-key wrap uses AES-ECB with the attacker's known passphrase-derived key, so the overflow payload is chosen plaintext. Up to 448 bytes past the 64-byte buffers corrupt list_head pointers and neighboring slab objects, yielding a write primitive for control-flow hijack.\nA:H - Corrupting keysig_list, embedded mutexes, and adjacent inode-cache/slab objects causes kernel oops or panic. The attacker can open the crafted file repeatedly to crash the system at will."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ecryptfs/keystore.c"],"versions":[{"version":"237fead619984cc48818fe12ee0ceada3f55b012","lessThan":"2cd21340163494d312836c77c9fbfe2530b3d075","status":"affected","versionType":"git"},{"version":"237fead619984cc48818fe12ee0ceada3f55b012","lessThan":"e2152d491ae62d96a32ed59778680a242af1fbc6","status":"affected","versionType":"git"},{"version":"237fead619984cc48818fe12ee0ceada3f55b012","lessThan":"d2802414081184f79a619ede178aeef3aa989793","status":"affected","versionType":"git"},{"version":"237fead619984cc48818fe12ee0ceada3f55b012","lessThan":"33e050cac841498b5175f0f385eee903fd98863c","status":"affected","versionType":"git"},{"version":"237fead619984cc48818fe12ee0ceada3f55b012","lessThan":"ccd13eff0e7356d2aa28b127b577e4e5ad4563f5","status":"affected","versionType":"git"},{"version":"237fead619984cc48818fe12ee0ceada3f55b012","lessThan":"14cb36a500a5a3afbc955dbf69dabc565f1a3b26","status":"affected","versionType":"git"},{"version":"237fead619984cc48818fe12ee0ceada3f55b012","lessThan":"a419c9ebfc9a40ee56aaad6dc68bfd67d400817b","status":"affected","versionType":"git"},{"version":"237fead619984cc48818fe12ee0ceada3f55b012","lessThan":"5babe9c177c364521e3e682b949c5a8c47f4a441","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ecryptfs/keystore.c"],"versions":[{"version":"2.6.19","status":"affected"},{"version":"0","lessThan":"2.6.19","status":"unaffected","versionType":"semver"},{"version":"5.10.270","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.221","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.188","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.157","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.109","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.50","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.4","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3-rc1","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.19","versionEndExcluding":"5.10.270"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.19","versionEndExcluding":"5.15.221"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.19","versionEndExcluding":"6.1.188"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.19","versionEndExcluding":"6.6.157"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.19","versionEndExcluding":"6.12.109"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.19","versionEndExcluding":"6.18.50"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.19","versionEndExcluding":"7.2.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.19","versionEndExcluding":"7.3-rc1"}]}]}],"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"}],"title":"ecryptfs: reject oversized encrypted_key_size in parse_tag_3_packet","x_generator":{"engine":"bippy-1.2.0"}}}}