From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 633BB3D47B1 for ; Wed, 3 Jun 2026 15:50:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780501846; cv=none; b=RESLWBemBs1i9FPYPJiiY/rbIQ3W8nAp+czSDDTsmTZnblMI0eIXMzXEhB7cShOxXEPOGrXEktw6/Cra662ra+A6UpgMGQJ+LmX6xGErD/DR8AQ+T4NIecx3EnRN8UJvtMBoBwo9kOtq/jq9gP3Njr+JbcBligEIj32UwihMohQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780501846; c=relaxed/simple; bh=rKu5poRzsk1pMeXXTaAjJGJC5dXxb/V0VMXm8m9bQs4=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=JVK7J+xA4MJ2IZZrtlBQqFdthv0CJqbMAHEle688Hy6mKkV1QhlMN4PhkOSikQu7WbZGts5bgkHgulVj59zr4K22oH+MJMksUcAv3UnSC0FVHLuume6ryDAH1Ku7uQcdq5PjdBqnpyK2vMtbIkQrYGqCHgu3BFr0MFm1qzjlP7Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=mQ+USRXu; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="mQ+USRXu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 54E671F00893; Wed, 3 Jun 2026 15:50:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780501845; bh=doxkNfODPT85JtG70r4LLD/ggGgO5WfdV1RBVxkDfSM=; h=From:To:Cc:Subject:Date:Reply-To; b=mQ+USRXulUnJ4OgpR0/4QtGU5PmdOvw6IDoHa7NPvlbs0iCs5mU7atNDTG7V0YQag KbkrQnGMDpK8Z+zgeUazI+WZ+olCOYwVpaZYDQYgExv4BZ5N6zWr0nvCTKt6Bx1IV7 pqJ5rdBgx4sNpYnRQumvZLfL67T6s2ETw2AwPDLM= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-46253: pstore/ram: fix buffer overflow in persistent_ram_save_old() Date: Wed, 3 Jun 2026 17:49:42 +0200 Message-ID: <2026060335-CVE-2026-46253-a855@gregkh> X-Mailer: git-send-email 2.54.0 Reply-To: , Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=5356; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=bjG8ThgToWpetYDuAc5Ct+rCzNy/xUK/qKnOOLlqPVw=; b=owGbwMvMwCRo6H6F97bub03G02pJDFkKvvxaPzYacnBxCXmIzJ0d/aXthswujXsP3zVv9Y1l+ tD68/arjlgWBkEmBlkxRZYv23iO7q84pOhlaHsaZg4rE8gQBi5OAZjIpkcM8+t/rs033yuhFcxz 6o4s44O9AikFDAzzbLg/z1XiO3zAcU5O70Umo9gvB2WZAA== X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman Description =========== 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 Linux kernel CVE team has assigned CVE-2026-46253 to this issue. Affected and fixed versions =========================== Issue introduced in 3.5 with commit 201e4aca5aa179e6c69a4dcd36a3562e56b8d670 and fixed in 5.10.252 with commit 58bda5a1d1ee98254383ef34f76b2c35140513ea Issue introduced in 3.5 with commit 201e4aca5aa179e6c69a4dcd36a3562e56b8d670 and fixed in 5.15.202 with commit 06d2c8bd108cea503f6f6e13e47495ed1085275f Issue introduced in 3.5 with commit 201e4aca5aa179e6c69a4dcd36a3562e56b8d670 and fixed in 6.1.165 with commit 2fa9a047c6a50ec80c3890dd623b85e237f0d1fd Issue introduced in 3.5 with commit 201e4aca5aa179e6c69a4dcd36a3562e56b8d670 and fixed in 6.6.128 with commit cff0ef043e16feb5a02307c8f9d0117a96c5587c Issue introduced in 3.5 with commit 201e4aca5aa179e6c69a4dcd36a3562e56b8d670 and fixed in 6.12.75 with commit 9a6fc69a570c0780834246d52c856cc3dbc2605f Issue introduced in 3.5 with commit 201e4aca5aa179e6c69a4dcd36a3562e56b8d670 and fixed in 6.18.14 with commit 4f73486ca822305c1cf5b8ebc0b53a6ab3801a81 Issue introduced in 3.5 with commit 201e4aca5aa179e6c69a4dcd36a3562e56b8d670 and fixed in 6.19.4 with commit 7cfe964e61c0ab667abd5f5b68e0acbf783efa4f Issue introduced in 3.5 with commit 201e4aca5aa179e6c69a4dcd36a3562e56b8d670 and fixed in 7.0 with commit 5669645c052f235726a85f443769b6fc02f66762 Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2026-46253 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: fs/pstore/ram_core.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/58bda5a1d1ee98254383ef34f76b2c35140513ea https://git.kernel.org/stable/c/06d2c8bd108cea503f6f6e13e47495ed1085275f https://git.kernel.org/stable/c/2fa9a047c6a50ec80c3890dd623b85e237f0d1fd https://git.kernel.org/stable/c/cff0ef043e16feb5a02307c8f9d0117a96c5587c https://git.kernel.org/stable/c/9a6fc69a570c0780834246d52c856cc3dbc2605f https://git.kernel.org/stable/c/4f73486ca822305c1cf5b8ebc0b53a6ab3801a81 https://git.kernel.org/stable/c/7cfe964e61c0ab667abd5f5b68e0acbf783efa4f https://git.kernel.org/stable/c/5669645c052f235726a85f443769b6fc02f66762