VulnerabilityPublished 27 May 2026Updated 6 Nov 2026

CVE-2026-45851: Linux kernel · efi: Fix reservation of unaccepted memory table

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in e649b5916725c68f44ebf45fb396df563c5dbaf2 : update Linux kernel when convenient.

Data as of 6 Nov 2026, 16:04 UTC

Severity

Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-06.

Patch

Available – fixed in e649b5916725c68f44ebf45fb396df563c5dbaf2, ba6b6f1502fa55621d1db23f253d54322bdbe4e0, b7bc182ec1846be437351e44164089d988f9d0dd +2

Exploitation evidence

Disclosed: evidence found.
CVE published 27 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 8dbe33956d96c9d066ef15ca933ede30748198b2, < e649b5916725c68f44ebf45fb396df563c5dbaf2	Fixed in e649b5916725c68f44ebf45fb396df563c5dbaf2
LinuxLinux	Affected ≥ 8dbe33956d96c9d066ef15ca933ede30748198b2, < ba6b6f1502fa55621d1db23f253d54322bdbe4e0	Fixed in ba6b6f1502fa55621d1db23f253d54322bdbe4e0
LinuxLinux	Affected ≥ 8dbe33956d96c9d066ef15ca933ede30748198b2, < b7bc182ec1846be437351e44164089d988f9d0dd	Fixed in b7bc182ec1846be437351e44164089d988f9d0dd
LinuxLinux	Affected ≥ 8dbe33956d96c9d066ef15ca933ede30748198b2, < 0862438c90487e79822d5647f854977d50381505	Fixed in 0862438c90487e79822d5647f854977d50381505
LinuxLinux	Affected ≥ 8dbe33956d96c9d066ef15ca933ede30748198b2, < 9b18bf59977f5c5bc3b11b210520f62500a7adf3	Fixed in 9b18bf59977f5c5bc3b11b210520f62500a7adf3
LinuxLinux	Affected =6.6	Fixed in–

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.

References

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