{ "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": "2026-10-19T08:49:39.398Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:49:39.398Z" }, "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", "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" } ] } ] } ], "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" } } } }