FKIE_CVE-2026-89607
Vulnerability from fkie_nvd - Published: 2026-09-11 20:19 - Updated: 2026-09-14 13:19
Severity
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]
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/ecryptfs/keystore.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "2cd21340163494d312836c77c9fbfe2530b3d075",
"status": "affected",
"version": "237fead619984cc48818fe12ee0ceada3f55b012",
"versionType": "git"
},
{
"lessThan": "e2152d491ae62d96a32ed59778680a242af1fbc6",
"status": "affected",
"version": "237fead619984cc48818fe12ee0ceada3f55b012",
"versionType": "git"
},
{
"lessThan": "d2802414081184f79a619ede178aeef3aa989793",
"status": "affected",
"version": "237fead619984cc48818fe12ee0ceada3f55b012",
"versionType": "git"
},
{
"lessThan": "33e050cac841498b5175f0f385eee903fd98863c",
"status": "affected",
"version": "237fead619984cc48818fe12ee0ceada3f55b012",
"versionType": "git"
},
{
"lessThan": "ccd13eff0e7356d2aa28b127b577e4e5ad4563f5",
"status": "affected",
"version": "237fead619984cc48818fe12ee0ceada3f55b012",
"versionType": "git"
},
{
"lessThan": "14cb36a500a5a3afbc955dbf69dabc565f1a3b26",
"status": "affected",
"version": "237fead619984cc48818fe12ee0ceada3f55b012",
"versionType": "git"
},
{
"lessThan": "a419c9ebfc9a40ee56aaad6dc68bfd67d400817b",
"status": "affected",
"version": "237fead619984cc48818fe12ee0ceada3f55b012",
"versionType": "git"
},
{
"lessThan": "5babe9c177c364521e3e682b949c5a8c47f4a441",
"status": "affected",
"version": "237fead619984cc48818fe12ee0ceada3f55b012",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"fs/ecryptfs/keystore.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.19"
},
{
"lessThan": "2.6.19",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.270",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.221",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.188",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.157",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.109",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.50",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.4",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3-rc1",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"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 \u003e 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-\u003ekey, decrypted_key, decrypted_key_size) writes\n into crypt_stat-\u003ekey[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-\u003ekey_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 \u003c= 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]"
}
],
"id": "CVE-2026-89607",
"lastModified": "2026-09-14T13:19:14.910",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-09-11T20:19:45.723",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/14cb36a500a5a3afbc955dbf69dabc565f1a3b26"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/2cd21340163494d312836c77c9fbfe2530b3d075"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/33e050cac841498b5175f0f385eee903fd98863c"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/5babe9c177c364521e3e682b949c5a8c47f4a441"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/a419c9ebfc9a40ee56aaad6dc68bfd67d400817b"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/ccd13eff0e7356d2aa28b127b577e4e5ad4563f5"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/d2802414081184f79a619ede178aeef3aa989793"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/e2152d491ae62d96a32ed59778680a242af1fbc6"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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