CyberSecBulletin
CVE-2026-45878NVD status: Modified

Linux: Out-of-bounds Read

Published Updated By the CyberSecBulletin desk

CVE-2026-45878 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 971bf8e61e9b4abaacf9b35eaf76ec222758f9d6, a0d367e13db63a6ed76ee0d0a8c3a58c1fa98488, 2b36c0c1bcbbe15f6cfa9652084b3124c835a150 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.21% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 971bf8e61e9b4abaacf9b35eaf76ec222758f9d6 or a0d367e13db63a6ed76ee0d0a8c3a58c1fa98488 or 2b36c0c1bcbbe15f6cfa9652084b3124c835a150 or 3c38a0f07aa2bfef2b219b1f045534ad93f85afd, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.6.128 or 6.12.75 or 6.18.14 or 6.19.4, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxe0f85f4690d089cc1a60337decafb1acf7eec45e up to, but not including, 971bf8e61e9b4abaacf9b35eaf76ec222758f9d6; e0f85f4690d089cc1a60337decafb1acf7eec45e up to, but not including, a0d367e13db63a6ed76ee0d0a8c3a58c1fa98488; e0f85f4690d089cc1a60337decafb1acf7eec45e up to, but not including, 2b36c0c1bcbbe15f6cfa9652084b3124c835a150; e0f85f4690d089cc1a60337decafb1acf7eec45e up to, but not including, 3c38a0f07aa2bfef2b219b1f045534ad93f85afd; e0f85f4690d089cc1a60337decafb1acf7eec45e up to, but not including, 5a19302cab5cec7ae7f1a60c619951e6c17d8742; 6.5971bf8e61e9b4abaacf9b35eaf76ec222758f9d6, a0d367e13db63a6ed76ee0d0a8c3a58c1fa98488, 2b36c0c1bcbbe15f6cfa9652084b3124c835a150, 3c38a0f07aa2bfef2b219b1f045534ad93f85afd, 5a19302cab5cec7ae7f1a60c619951e6c17d8742
LinuxLinux Kernel6.5 up to, but not including, 6.6.128; 6.7 up to, but not including, 6.12.75; 6.13 up to, but not including, 6.18.14; 6.19 up to, but not including, 6.19.46.6.128, 6.12.75, 6.18.14, 6.19.4

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: drm/amdkfd: Fix watch_id bounds checking in debug address watch v2 The address watch clear code receives watch_id as an unsigned value (u32), but some helper functions were using a signed int and checked bits by shifting with watch_id. If a very large watch_id is passed from userspace, it can be converted to a negative value. This can cause invalid shifts and may access memory outside the watch_points array. drm/amdkfd: Fix watch_id bounds checking in debug address watch v2 Fix this by checking that watch_id is within MAX_WATCH_ADDRESSES before using it. Also use BIT(watch_id) to test and clear bits safely. This keeps the behavior unchanged for valid watch IDs and avoids undefined behavior for invalid ones. Fixes the below: drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_debug.c:448 kfd_dbg_trap_clear_dev_address_watch() error: buffer overflow 'pdd->watch_points' 4 <= u32max user_rl='0-3,2147483648-u32max' uncapped drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_debug.c 433 int kfd_dbg_trap_clear_dev_address_watch(struct kfd_process_device *pdd, 434 uint32_t watch_id) 435 { 436 int r; 437 438 if (!kfd_dbg_owns_dev_watch_id(pdd, watch_id)) kfd_dbg_owns_dev_watch_id() doesn't check for negative values so if watch_id is larger than INT_MAX it leads to a buffer overflow. (Negative shifts are undefined). 439 return -EINVAL; 440 441 if (!pdd->dev->kfd->shared_resources.enable_mes) { 442 r = debug_lock_and_unmap(pdd->dev->dqm); 443 if (r) 444 return r; 445 } 446 447 amdgpu_gfx_off_ctrl(pdd->dev->adev, false); --> 448 pdd->watch_points[watch_id] = pdd->dev->kfd2kgd->clear_address_watch( 449 pdd->dev->adev, 450 watch_id); v2: (as per, Jonathan Kim) - Add early watch_id >= MAX_WATCH_ADDRESSES validation in the set path to match the clear path. - Drop the redundant bounds check in kfd_dbg_owns_dev_watch_id().

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that provides appropriate memory abstractions.

More Out-of-bounds Read vulnerabilities (CWE-125)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Read vulnerabilities

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