CVE-2025-68788 — fsnotify: do not generate ACCESS/MODIFY events on child for special files

Affected: Linux, Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP, Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP, Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

In the Linux kernel, the following vulnerability has been resolved:

fsnotify: do not generate ACCESS/MODIFY events on child for special files

inotify/fanotify do not allow users with no read access to a file to subscribe to events (e.g. IN_ACCESS/IN_MODIFY), but they do allow the same user to subscribe for watching events on children when the user has access to the parent directory (e.g. /dev).

Users with no read access to a file but with read access to its parent directory can still stat the file and see if it was accessed/modified via atime/mtime change.

The same is not true for special files (e.g. /dev/null). Users will not generally observe atime/mtime changes when other users read/write to special files, only when someone sets atime/mtime via utimensat().

Align fsnotify events with this stat behavior and do not generate ACCESS/MODIFY events to parent watchers on read/write of special files. The events are still generated to parent watchers on utimensat(). This closes some side-channels that could be possibly used for information exfiltration [1].

[1] https://snee.la/pdf/pubs/file-notification-attacks.pdf

USN-8096-1 — linux, linux-aws, linux-gcp, linux-gkeop, linux-ibm, linux-ibm-5.15, linux-intel-iotg, linux-kvm, linux-lowlatency, lin…

Affected: Ubuntu:Pro:20.04:LTS: linux-ibm-5.15, Ubuntu:Pro:20.04:LTS: linux-nvidia-tegra-5.15, Ubuntu:22.04:LTS: linux, Ubuntu:22.04:LTS: linux-aws, Ubuntu:22.04:LTS: linux-gcp, Ubuntu:22.04:LTS: linux-gkeop, Ubuntu:22.04:LTS: linux-ibm, Ubuntu:22.04:LTS: linux-intel-iotg, Ubuntu:22.04:LTS: linux-kvm, Ubuntu:22.04:LTS: linux-lowlatency and 4 more

Qualys discovered that several vulnerabilities existed in the AppArmor Linux kernel Security Module (LSM). An unprivileged local attacker could use these issues to load, replace, and remove arbitrary AppArmor profiles causing denial of service, exposure of sensitive information (kernel memory), local privilege escalation, or possibly escape a container. (LP: #2143853)

Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - PowerPC architecture; - x86 architecture; - Block layer subsystem; - Cryptographic API; - ACPI drivers; - ATM drivers; - Drivers core; - Network block device driver; - Bluetooth drivers; - Character device driver; - TPM device driver; - Data acquisition framework and drivers; - Counter interface drivers; - CPU frequency scaling framework; - Intel Stratix 10 firmware drivers; - GPU drivers; - HID subsystem; - Hardware monitoring drivers; - IIO subsystem; - InfiniBand drivers; - Input Device core drivers; - Input Device (Tablet) drivers; - ISDN/mISDN subsystem; - Macintosh device drivers; - Media drivers; - MOST (Media Oriented Systems Transport) drivers; - MTD block device drivers; - Network drivers; - Mellanox network drivers; - Texas Instruments network drivers; - Ethernet team driver; - MediaTek network drivers; - NVME drivers; - PA-RISC drivers; - PCI subsyste…

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CVE-2025-68788 — fsnotify: do not generate ACCESS/MODIFY events on child for special files

USN-8096-1 — linux, linux-aws, linux-gcp, linux-gkeop, linux-ibm, linux-ibm-5.15, linux-intel-iotg, linux-kvm, linux-lowlatency, lin…