CVE-2026-46253 — pstore/ram: fix buffer overflow in persistent_ram_save_old()

Affected: Linux

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

pstore/ram: fix buffer overflow in persistent_ram_save_old()

persistent_ram_save_old() can be called multiple times for the same persistent_ram_zone (e.g., via ramoops_pstore_read -> ramoops_get_next_prz for PSTORE_TYPE_DMESG records).

Currently, the function only allocates prz->old_log when it is NULL, but it unconditionally updates prz->old_log_size to the current buffer size and then performs memcpy_fromio() using this new size. If the buffer size has grown since the first allocation (which can happen across different kernel boot cycles), this leads to:

1. A heap buffer overflow (OOB write) in the memcpy_fromio() calls 2. A subsequent OOB read when ramoops_pstore_read() accesses the buffer using the incorrect (larger) old_log_size

The KASAN splat would look similar to: BUG: KASAN: slab-out-of-bounds in ramoops_pstore_read+0x... Read of size N at addr ... by task ...

The conditions are likely extremely hard to hit:

0. Crash with a ramoops write of less-than-record-max-size bytes. 1. Reboot: ramoops registers, pstore_get_records(0) reads old crash, allocates old_log with size X 2. Crash handler registered, timer started (if pstore_update_ms >= 0) 3. Oops happens (non-fatal, system continues) 4. pstore_dump() writes oops via ramoops_pstore_write() size Y (>X) 5. pstore_new_entry = 1, pstore_timer_kick() called 6. System continues running (not a panic oops) 7. Timer fires af…

USN-8492-1 — linux, linux-aws, linux-aws-fips, linux-gcp, linux-gcp-fips, linux-ibm, linux-nvidia, linux-nvidia-6.8, linux-oracle, l…

Affected: Ubuntu:22.04:LTS: linux-nvidia-6.8, Ubuntu:Pro:Realtime:22.04:LTS: linux-realtime-6.8, Ubuntu:24.04:LTS: linux, Ubuntu:24.04:LTS: linux-aws, Ubuntu:24.04:LTS: linux-gcp, Ubuntu:24.04:LTS: linux-ibm, Ubuntu:24.04:LTS: linux-nvidia, Ubuntu:24.04:LTS: linux-oracle, Ubuntu:Pro:Realtime:24.04:LTS: linux-realtime, Ubuntu:Pro:FIPS-updates:24.04:LTS: linux-aws-fips and 1 more

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: - ARM64 architecture; - MIPS architecture; - PowerPC architecture; - x86 architecture; - Block layer subsystem; - Cryptographic API; - ACPI drivers; - ATM drivers; - RNBD block device driver; - Ublk userspace block driver; - Bus devices; - Character device driver; - TPM device driver; - Clock framework and drivers; - Clocksource drivers; - CPU idle management framework; - Hardware crypto device drivers; - DMA engine subsystem; - EFI core; - GPIO subsystem; - GPU drivers; - HID subsystem; - Hardware monitoring drivers; - IIO subsystem; - InfiniBand drivers; - IOMMU subsystem; - Multiple devices driver; - Media drivers; - Multifunction device drivers; - Broadcom VK accelerator driver; - MOST (Media Oriented Systems Transport) drivers; - MTD block device drivers; - Ethernet bonding driver; - Network drivers; - Mellanox network drivers; - STMicroelectronics network drivers; - NTB driver; - NVME drivers; - PCI subsystem; - Performance monitor drivers; - Pin controllers subsystem; - x86 platform drivers; - Power supply drivers; - RapidIO drivers; - RAS (Reliability, Availability, Serviceability) subsystem; - Remote Processor subsystem; - RPMSG subsystem; - S/390 drivers; - SCSI subsystem; - MediaTek SoC dr…

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CVE-2026-46253 — pstore/ram: fix buffer overflow in persistent_ram_save_old()

USN-8492-1 — linux, linux-aws, linux-aws-fips, linux-gcp, linux-gcp-fips, linux-ibm, linux-nvidia, linux-nvidia-6.8, linux-oracle, l…