Linux: Out-of-bounds Read
CVE-2026-45851 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.1 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 b7bc182ec1846be437351e44164089d988f9d0dd, ba6b6f1502fa55621d1db23f253d54322bdbe4e0, 9b18bf59977f5c5bc3b11b210520f62500a7adf3 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 0.16% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to b7bc182ec1846be437351e44164089d988f9d0dd or ba6b6f1502fa55621d1db23f253d54322bdbe4e0 or 9b18bf59977f5c5bc3b11b210520f62500a7adf3 or e649b5916725c68f44ebf45fb396df563c5dbaf2, whichever matches your release line, or a later version.
- 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
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 8dbe33956d96c9d066ef15ca933ede30748198b2 up to, but not including, b7bc182ec1846be437351e44164089d988f9d0dd; 8dbe33956d96c9d066ef15ca933ede30748198b2 up to, but not including, ba6b6f1502fa55621d1db23f253d54322bdbe4e0; 8dbe33956d96c9d066ef15ca933ede30748198b2 up to, but not including, 9b18bf59977f5c5bc3b11b210520f62500a7adf3; 8dbe33956d96c9d066ef15ca933ede30748198b2 up to, but not including, e649b5916725c68f44ebf45fb396df563c5dbaf2; 8dbe33956d96c9d066ef15ca933ede30748198b2 up to, but not including, 0862438c90487e79822d5647f854977d50381505; 6.6 | b7bc182ec1846be437351e44164089d988f9d0dd, ba6b6f1502fa55621d1db23f253d54322bdbe4e0, 9b18bf59977f5c5bc3b11b210520f62500a7adf3, e649b5916725c68f44ebf45fb396df563c5dbaf2, 0862438c90487e79822d5647f854977d50381505 |
| Linux | Linux Kernel | 6.6.1 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, 6.19.4; 6.6 | 6.6.128, 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
- NoneNothing can be modified.
- 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:N/A:H. Scored by NVD.
Official description
In the Linux kernel, the following vulnerability has been resolved: efi: Fix reservation of unaccepted memory table The reserve_unaccepted() function incorrectly calculates the size of the memblock reservation for the unaccepted memory table. It aligns the size of the table, but fails to account for cases where the table's starting physical address (efi.unaccepted) is not page-aligned. If the table starts at an offset within a page and its end crosses into a subsequent page that the aligned size does not cover, the end of the table will not be reserved. This can lead to the table being overwritten or inaccessible, causing a kernel panic in accept_memory(). This issue was observed when starting Intel TDX VMs with specific memory sizes (e.g., > 64GB). Fix this by calculating the end address first (including the unaligned start) and then aligning it up, ensuring the entire range is covered by the reservation.
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.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/0862438c90487e79822d5647f854977d50381505
- git.kernel.org/stable/c/9b18bf59977f5c5bc3b11b210520f62500a7adf3
- git.kernel.org/stable/c/b7bc182ec1846be437351e44164089d988f9d0dd
- git.kernel.org/stable/c/ba6b6f1502fa55621d1db23f253d54322bdbe4e0
- git.kernel.org/stable/c/e649b5916725c68f44ebf45fb396df563c5dbaf2
Recent Out-of-bounds Read vulnerabilities
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
- 8.2 High severity
- 7.1 High severity
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