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NVD / CVE Program· CNA Linux

CVE-2026-23100: mm/hugetlb: fix hugetlb_pmd_shared()

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.14% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 3a18b452dd5f7f1652c2e92f8ae769aa17a66c9e, 5.10.253, 5.15.203; azl3 kernel 6.6.126.1-1 on Azure Linux 3.0 6.6.130.1-1; cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0 Release Notes.

Low priority for now. Upgrade to Linux Linux 3a18b452dd5f7f1652c2e92f8ae769aa17a66c9e, 5.10.253, 5.15.203; azl3 kernel 6.6.126.1-1 on Azure Linux 3.0 6.6.130.1-1; cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0 Release Notes or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: mm/hugetlb: fix hugetlb_pmd_shared() Patch series "mm/hugetlb: fixes for PMD table sharing (incl. using mmu_gather)", v3. One functional fix, one performance regression fix, and two related comment fixes. I cleaned up my prototype I recently shared [1] for the performance fix, deferring most of the cleanups I had in the prototype to a later point. While doing that I identified the other things. The goal of this patch set is to be backported to stable trees "fairly" easily. At least patch #1 and #4. Patch #1 fixes hugetlb_pmd_shared() not detecting any sharing Patch #2 + #3 are simple comment fixes that patch #4 interacts with. Patch #4 is a fix for the reported performance regression due to excessive IPI broadcasts during fork()+exit(). The last patch is all about TLB flushes, IPIs and mmu_gather. Read: complicated There are plenty of cleanups in the future to be had + one reasonable optimization on x86. But that's all out of scope for this series. Runtime tested, with a focus on fixing the performance regression using the original reproducer [2] on x86. This patch (of 4): We switched from (wrongly) using the page count to an independent shared count. Now, shared page tables have a refcount of 1 (excluding speculative references) and instead use ptdesc->pt_share_count to identify sharing. We didn't convert hugetlb_pmd_shared(), so right now, we would never detect a shared PMD table as such, because sharing/unsharing no longer touches the refcount of a PMD table. Page migration, like mbind() or migrate_pages() would allow for migrating folios mapped into such shared PMD tables, even though the folios are not exclusive. In smaps we would account them as "private" although they are "shared", and we would be wrongly setting the PM_MMAP_EXCLUSIVE in the pagemap interface. Fix it by properly using ptdesc_pmd_is_shared() in hugetlb_pmd_shared().

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Feb 4, 2026
Updated
Oct 15, 2026
EPSS
0.1% · 3th percentile
CWE
—

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.10.239 and later · before 5.11
  • linux linux kernel5.15.186 and later · before 5.16
  • linux linux kernel6.1.142 and later · before 6.2
  • linux linux kernel6.6.72 and later · before 6.6.127
  • linux linux kernel6.12.9 and later · before 6.12.74
  • linux linux kernel6.13.1 and later · before 6.18.8
  • linux linux kernel6.13
  • linux linux kernel6.19

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 6.13affected
    • 94b4b41d0cdf5cfd4d4325bc0e6e9e0d0e996133 and later · before 8ae48255bcb17b32436be97553dca848730d365faffected · git
    • 8410996eb6fea116fe1483ed977aacf580eee7b4 and later · before bf3c2affe245cf831866ddc8f736ae6a22cdc11caffected · git
    • 02333ac1c35370517a19a4a131332a9690c6a5c7 and later · before 5b2aec77f92265a9028c5f632bdd9af5b57ec3a3affected · git
    • 56b274473d6e7e7375f2d0a2b4aca11d67c6b52f and later · before 51dcf459845fd28f5a0d83d408a379b274ec5cc5affected · git
    • 2e31443a0d18ae43b9d29e02bf0563f07772193d and later · before 3a18b452dd5f7f1652c2e92f8ae769aa17a66c9eaffected · git
    • 59d9094df3d79443937add8700b2ef1a866b1081 and later · before 69c4e241ff13545d410a8b2a688c932182a858bfaffected · git
    • 59d9094df3d79443937add8700b2ef1a866b1081 and later · before ca1a47cd3f5f4c46ca188b1c9a27af87d1ab2216affected · git
    • 5.10.239 and later · before 5.10.253affected · semver
    • 5.15.186 and later · before 5.15.203affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.170-16.1.170-1
Debian:13linuxbefore 6.12.74-26.12.74-2
Debian:14linuxbefore 6.18.8-16.18.8-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-23097Feb 4, 2026 · migrate: correct lock ordering for hugetlb file folios
    22Monitor
  • ← EarlierCVE-2026-23099Feb 4, 2026 · bonding: limit BOND_MODE_8023AD to Ethernet devices
    28Monitor
  • Later →CVE-2026-23101Feb 4, 2026 · leds: led-class: Only Add LED to leds_list when it is fully ready
    18Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux3a18b452dd5f7f1652c2e92f8ae769aa17a66c9eVendor (CNA)
Linux Linux5.10.253Vendor (CNA)
Linux Linux5.15.203Vendor (CNA)
Linux Linux51dcf459845fd28f5a0d83d408a379b274ec5cc5Vendor (CNA)
Linux Linux5b2aec77f92265a9028c5f632bdd9af5b57ec3a3Vendor (CNA)
Linux Linux6.1.167Vendor (CNA)
Linux Linux6.12.74Vendor (CNA)
Linux Linux6.6.127Vendor (CNA)
Linux Linux69c4e241ff13545d410a8b2a688c932182a858bfVendor (CNA)
Linux Linux8ae48255bcb17b32436be97553dca848730d365fVendor (CNA)
Linux Linuxbf3c2affe245cf831866ddc8f736ae6a22cdc11cVendor (CNA)
Linux Linuxca1a47cd3f5f4c46ca188b1c9a27af87d1ab2216Vendor (CNA)
azl3 kernel 6.6.126.1-1 on Azure Linux 3.06.6.130.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0Release NotesMicrosoft (MSRC)
debian:linux6.1.170-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (10 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records