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DEBIAN-CVE-2026-46253
No affected components available
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 after pstore_update_ms milliseconds 8. pstore_timefunc() → schedule_work() → pstore_dowork() → pstore_get_records(1) 9. ramoops_get_next_prz() → persistent_ram_save_old() 10. buffer_size() returns Y, but old_log is X bytes 11. Y > X: memcpy_fromio() overflows heap Requirements: - a prior crash record exists that did not fill the record size (almost impossible since the crash handler writes as much as it can possibly fit into the record, capped by max record size and the kmsg buffer almost always exceeds the max record size) - pstore_update_ms >= 0 (disabled by default) - Non-fatal oops (system survives) Free and reallocate the buffer when the new size differs from the previously allocated size. This ensures old_log always has sufficient space for the data being copied.
The vulnerability requires local access to the device to be exploited. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data. There is a high impact on the availability of the system.
Exploitation activity has been observed. Apply available patches or mitigations urgently.
Probability that this vulnerability will be exploited in the wild within the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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