netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages() (CVE-2026-64216) | HOL Guard CVE

Critical · CVSS 9.8CVE-2026-64216

netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages()

Answer in brief

CVE-2026-64216 records a Critical severity (CVSS 9.8) vulnerability in netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Jul 24, 2026Updated Aug 27, 2026Source checked Sep 20, 2026First seen by HOL Aug 5, 2026Material review Aug 27, 2026

Upstream Advisory

Key facts

Risk: Critical · CVSS 9.8
Exploitation: Not marked as known exploited
Affected software: 8 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 9.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Affected products and reported versions
Product	Affected versions	Fixed versions
cpe:2.3:o:linux:linux_kernel::::::::	Not reported	Not reported
cpe:2.3:o:linux:linux_kernel:7.1:rc1::::::	Not reported	Not reported
cpe:2.3:o:linux:linux_kernel:7.1:rc2::::::	Not reported	Not reported
cpe:2.3:o:linux:linux_kernel:7.1:rc3::::::	Not reported	Not reported
cpe:2.3:o:linux:linux_kernel:7.1:rc4::::::	Not reported	Not reported

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=ee4cdf7ba857a894ad1650d6ab77669cbbfa329e <6080fa3ecfbb4448a3b47368629534c09b6ec750 \|\| >=ee4cdf7ba857a894ad1650d6ab77669cbbfa329e <3866d015f33aeedf81338dd99154703bef33faef \|\| >=ee4cdf7ba857a894ad1650d6ab77669cbbfa329e <dbe556972100fabb8e5a1b3d2163831ff07b1e8e	6080fa3ecfbb4448a3b47368629534c09b6ec750, 3866d015f33aeedf81338dd99154703bef33faef, dbe556972100fabb8e5a1b3d2163831ff07b1e8e
Linux/Linuxgeneric	6.12	Not reported
Linux/Linuxgeneric	>=ee4cdf7ba857a894ad1650d6ab77669cbbfa329e <d4ae8dba90b89e7bb4d1045d1cb26afbaf13ee5c \|\| >=ee4cdf7ba857a894ad1650d6ab77669cbbfa329e <6080fa3ecfbb4448a3b47368629534c09b6ec750 \|\| >=ee4cdf7ba857a894ad1650d6ab77669cbbfa329e <3866d015f33aeedf81338dd99154703bef33faef \|\| >=ee4cdf7ba857a894ad1650d6ab77669cbbfa329e <dbe556972100fabb8e5a1b3d2163831ff07b1e8e	d4ae8dba90b89e7bb4d1045d1cb26afbaf13ee5c, 6080fa3ecfbb4448a3b47368629534c09b6ec750, 3866d015f33aeedf81338dd99154703bef33faef, dbe556972100fabb8e5a1b3d2163831ff07b1e8e

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 6080fa3ecfbb4448a3b47368629534c09b6ec750; Linux/Linux to d4ae8dba90b89e7bb4d1045d1cb26afbaf13ee5c if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Jul 24, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 27, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 5, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages() netfs_unlock_abandoned_read_pages(rreq) accesses the index of the folios it is wanting to unlock and compares that to rreq->no_unlock_folio so that it doesn't unlock a folio being read for netfs_perform_write() or netfs_write_begin(). However, given that netfs_unlock_abandoned_read_pages() is called _after_ NETFS_RREQ_IN_PROGRESS is cleared, the one folio that it's not allowed to dereference is the one specified by ->no_unlock_folio as ownership immediately reverts to the caller. Fix this by storing the folio pointer instead and using that rather than the index. Also fix netfs_unlock_read_folio() where the same applies.

Quoted source text, attributed separately from HOL analysis.