> CVE-2026-64191

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PUBLISHED
2026-07-20 17:18
MODIFIED
2026-07-20 17:18
EPSS (Prob. Exploit)
0.17%
Top 94.3%
DATA SOURCES:
NVD 🔗 2026-07-20 RED HAT 🔗 2026-07-26 FIRST EPSS 🔗 2026-11-01 OSV 🔗 2026-10-26 MSRC 🔗 2026-11-02

> DESCRIPTION

In the Linux kernel, the following vulnerability has been resolved: i2c: stub: Reject I2C block transfers with invalid length The I2C_SMBUS_I2C_BLOCK_DATA case in stub_xfer() uses data->block[0] as the transfer length. The existing check only clamps it to avoid overrunning the chip->words[256] register array, but does not validate it against I2C_SMBUS_BLOCK_MAX (32), which is the limit of the union i2c_smbus_data.block buffer (34 bytes total). The driver is a development/test tool (CONFIG_I2C_STUB=m, not built by default) that must be loaded with a chip_addr= parameter. A local user with access to /dev/i2c-* can issue an I2C_SMBUS ioctl with I2C_SMBUS_I2C_BLOCK_DATA and data->block[0] > 32, causing stub_xfer() to read or write past the end of the union i2c_smbus_data.block buffer: BUG: KASAN: stack-out-of-bounds in stub_xfer (drivers/i2c/i2c-stub.c:223) Read of size 1 at addr ffff88800abcfd92 by task exploit/81 Call Trace: <TASK> stub_xfer (drivers/i2c/i2c-stub.c:223) __i2c_smbus_xfer (drivers/i2c/i2c-core-smbus.c:593) i2c_smbus_xfer (drivers/i2c/i2c-core-smbus.c:536) i2cdev_ioctl_smbus (drivers/i2c/i2c-dev.c:391) i2cdev_ioctl (drivers/i2c/i2c-dev.c:478) __x64_sys_ioctl (fs/ioctl.c:583) do_syscall_64 (arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) </TASK> The bug exists because i2c-stub implements .smbus_xfer directly, bypassing the I2C_SMBUS_BLOCK_MAX validation in i2c_smbus_xfer_emulated(). The I2C_SMBUS_BLOCK_DATA case in the same function correctly validates against I2C_SMBUS_BLOCK_MAX, but the I2C_SMBUS_I2C_BLOCK_DATA case does not. Fix by rejecting transfers with data->block[0] == 0 or data->block[0] > I2C_SMBUS_BLOCK_MAX with -EINVAL, consistent with both the I2C_SMBUS_BLOCK_DATA case in the same function and the I2C_SMBUS_I2C_BLOCK_DATA validation in i2c_smbus_xfer_emulated().

> AFFECTED_PRODUCTS

ℹ️ Aucun produit affecté n'a encore été publié par NVD pour cette CVE.

> RED HAT SECURITY ADVISORIES

Red Hat Security Advisory: kernel-rt security, bug fix, and enhancement update
An update for kernel-rt is now available for Red Hat Enterprise Linux 8. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System...
Red Hat Security Advisory: kernel security, bug fix, and enhancement update
An update for kernel is now available for Red Hat Enterprise Linux 9. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (C...
Red Hat Security Advisory: kernel security, bug fix, and enhancement update
An update for kernel is now available for Red Hat Enterprise Linux 8. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (C...
Red Hat Security Advisory: kernel security update
An update for kernel is now available for Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions and Red Hat Enterprise Linux 8.8 Telecommunications Update Service. Red Hat Product Security h...
Red Hat Security Advisory: kernel security update
An update for kernel is now available for Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support and Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On. Red Hat Prod...
Red Hat Security Advisory: kernel security, bug fix, and enhancement update
An update for kernel is now available for Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support and Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On. Red Hat Prod...
Red Hat Security Advisory: kernel security, bug fix, and enhancement update
An update for kernel is now available for Red Hat Enterprise Linux 9.6 Extended Update Support. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulne...
Red Hat Security Advisory: kernel security update
An update for kernel is now available for Red Hat Enterprise Linux 7 Extended Lifecycle Support. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vuln...
Red Hat Security Advisory: kernel-rt security update
An update for kernel-rt is now available for Red Hat Enterprise Linux 7 Extended Lifecycle Support. Red Hat Product Security has rated this update as having a security impact of Important. A Common V...
Red Hat Security Advisory: kernel security, bug fix, and enhancement update
An update for kernel is now available for Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions. Red Hat Product Security has rated this update as having a security impact of Important. A Co...
Red Hat Security Advisory: kernel security, bug fix, and enhancement update
An update for kernel is now available for Red Hat Enterprise Linux 10.0 Extended Update Support. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vuln...
Red Hat Security Advisory: kernel security, bug fix, and enhancement update
An update for kernel is now available for Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions. Red Hat Product Security has rated this update as having a security impact of Important. A Co...
Red Hat Security Advisory: kernel-rt security, bug fix, and enhancement update
An update for kernel-rt is now available for Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions. Red Hat Product Security has rated this update as having a security impact of Important. A...
Red Hat Security Advisory: kernel security, bug fix, and enhancement update
An update for kernel is now available for Red Hat Enterprise Linux 10. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (...
Red Hat Security Advisory: kernel security, bug fix, and enhancement update
An update for kernel is now available for Red Hat Enterprise Linux 10. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (...

> RED HAT SEVERITY ASSESSMENT

THREAT SEVERITY
Important

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

i2c: stub: Reject I2C block transfers with invalid length

AFFECTED PACKAGES:
Unknown / Unknown
Linux / Kernel

> HISTORIQUE DES MODIFICATIONS

Première apparition
20/07/2026 17:18
Source: NVD
📊 ENRICHISSEMENT 26/07/2026 05:01
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 21/07/2026 23:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 21/07/2026 22:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 21/07/2026 21:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 21/07/2026 20:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 21/07/2026 19:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 21/07/2026 18:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 21/07/2026 17:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 21/07/2026 16:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 21/07/2026 15:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 21/07/2026 14:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 21/07/2026 13:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 21/07/2026 12:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
N/A
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 21/07/2026 12:30
REDHAT
Champ modifié: Red Hat
Ancienne valeur:
Non
Nouvelle valeur:
Oui
Total des modifications: 14 Dernière mise à jour: 3 months ago

> REFERENCES

https://git.kernel.org/stable/c/0526931b16e5a118d367b7bfce7d797e63f7ac69
https://git.kernel.org/stable/c/1c4ffe6b4f04365485ed58d64c9bb86b46fc9037
https://git.kernel.org/stable/c/21e87f336ac6303fed54a69b1d0d79a23b25c8d0
https://git.kernel.org/stable/c/3fd225f3e4cd67ec8ddab1afed9da03c7c43537c
https://git.kernel.org/stable/c/4bd8635f28c135a08aac6badcd7d9b5cdb34335f
https://git.kernel.org/stable/c/5f4d2bd028ebb6e4c09a9d64842546022321d4a7
https://git.kernel.org/stable/c/6036b5067a8199ba7a2dc7b377d4b9dd276d5f9e
https://git.kernel.org/stable/c/7e9072dbd5f2f17934751873450d2c22080ead80
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