efi: Fix reservation of unaccepted memory table
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · None · High
- Fix status
- Partial Red Hat: 2 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 6.6 and later | 6.6.128, 6.12.75, 6.18.14, 6.19.4, 7.0 | Patch available | CNA |
- Linux VendorLinux Affected 6.6 and later Fixed in 6.6.128, 6.12.75, 6.18.14, 6.19.4, 7.0 Patch available CNA
CPE configurations NVD · 7
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 6.6.1 to before 6.6.128; 6.7 to before 6.12.75; 6.13 to before 6.18.14; 6.19 to before 6.19.4 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.6:-:*:*:*:*:*:* | 6.6 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.6:rc3:*:*:*:*:*:* | 6.6 rc3 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.6:rc4:*:*:*:*:*:* | 6.6 rc4 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.6:rc5:*:*:*:*:*:* | 6.6 rc5 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.6:rc6:*:*:*:*:*:* | 6.6 rc6 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.6:rc7:*:*:*:*:*:* | 6.6 rc7 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 6.6.1 to before 6.6.128; 6.7 to before 6.12.75; 6.13 to before 6.18.14; 6.19 to before 6.19.4 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.6:-:*:*:*:*:*:* Versions 6.6 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.6:rc3:*:*:*:*:*:* Versions 6.6 rc3 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.6:rc4:*:*:*:*:*:* Versions 6.6 rc4 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.6:rc5:*:*:*:*:*:* Versions 6.6 rc5 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.6:rc6:*:*:*:*:*:* Versions 6.6 rc6 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.6:rc7:*:*:*:*:*:* Versions 6.6 rc7 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.6.128, 6.12.75, 6.18.14, 6.19.4, 7.0
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 3 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
Timeline
- 2026-10-02 Threatist record created from CVE-2026-45851
- 2026-10-03 Alias added: GHSA-r9jv-8h68-mr7c
- 2026-11-06 CISA SSVC decision points changed
References
Patch 5
- https://git.kernel.org/stable/c/b7bc182ec1846be437351e44164089d988f9d0dd
- https://git.kernel.org/stable/c/ba6b6f1502fa55621d1db23f253d54322bdbe4e0
- https://git.kernel.org/stable/c/9b18bf59977f5c5bc3b11b210520f62500a7adf3
- https://git.kernel.org/stable/c/e649b5916725c68f44ebf45fb396df563c5dbaf2
- https://git.kernel.org/stable/c/0862438c90487e79822d5647f854977d50381505
More Linux Kernel vulnerabilities
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- TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2026-45851 · CVE Program
- CVE-2026-45851 · NVD
- FIRST EPSS
- GHSA-r9jv-8h68-mr7c · GitHub Advisory Database · CC BY 4.0
- CVE-2026-45851 · Red Hat security data · CC BY 4.0
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