CVE-2026-68453
In the Linux kernel, the following vulnerability has been resolved:
s390/zcrypt: Fix buffer over-read in cca_cipher2protkey
Add validation of both the actual key buffer size and token length fields in all the cca_check_sec*token() functions. Additionally check in cca_gencipherkey() for possible underflow with returned key size.
The CCA token structures contain user-controlled len fields that were used in operations without proper validation against both the actual buffer size and minimum token structure size.
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An attacker could set this field larger than the actual buffer size, leading to reading beyond buffer boundaries. This may result in a kernel crash or exposure of memory via sending this as part of a request down to the crypto card. Also an attacker could have used a very small len value and thus enforce a buffer under-run which may produce similar effects as a over-read.
So now a key must - key buf length must be at least sizeof the token struct - the key len field inside the token must fit into the range of sizeof key token struct ... key buf length
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
- Puntuación base: 7.1
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.16%
- Percentil entre todas las CVEs puntuadas: 5
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1068Exploitation for Privilege Escalationprivilege escalation85 % - Impacto principal
T1005Data from Local Systemcollection80 % - Impacto secundario
T1499.004Application or System Exploitationimpact75 %
Vulnerabilidad local (AV:L, PR:L) sin interacción del usuario que permite lectura de memoria del kernel (C:H) y denegación de servicio (A:H) mediante validación insuficiente de campos en estructuras de token CCA.
Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
Referencias
JSON original (NVD)
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{
"id": "CVE-2026-68453",
"cveTags": [],
"metrics": {
"cvssMetricV31": [
{
"type": "Secondary",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 7.1,
"attackVector": "LOCAL",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
"integrityImpact": "NONE",
"userInteraction": "NONE",
"attackComplexity": "LOW",
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"programFiles": [
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"drivers/s390/crypto/zcrypt_ccamisc.c",
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{
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{
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"version": "5.4"
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{
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"version": "0",
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"versionType": "semver"
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{
"status": "unaffected",
"version": "6.18.44",
"versionType": "semver",
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{
"status": "unaffected",
"version": "7.1.8",
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{
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"versionType": "original_commit_for_fix",
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"programFiles": [
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"drivers/s390/crypto/zcrypt_ccamisc.c",
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"published": "2026-08-13T15:19:58.093",
"references": [
{
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/zcrypt: Fix buffer over-read in cca_cipher2protkey\n\nAdd validation of both the actual key buffer size and token length\nfields in all the cca_check_sec*token() functions. Additionally check\nin cca_gencipherkey() for possible underflow with returned key size.\n\nThe CCA token structures contain user-controlled len fields that\nwere used in operations without proper validation against both the\nactual buffer size and minimum token structure size. An attacker\ncould set this field larger than the actual buffer size, leading to\nreading beyond buffer boundaries. This may result in a kernel crash or\nexposure of memory via sending this as part of a request down to the\ncrypto card. Also an attacker could have used a very small len value\nand thus enforce a buffer under-run which may produce similar effects\nas a over-read.\n\nSo now a key must\n- key buf length must be at least sizeof the token struct\n- the key len field inside the token must fit into the range of\n sizeof key token struct ... key buf length"
}
],
"lastModified": "2026-08-17T06:17:54.427",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}