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TI-2026-48167 Aliases CVE-2026-68388GHSA-h6fv-x4pg-r56c

smb/client: handle overlapping allocated ranges in fallocate

Priority MEDIUM 49CWE-125Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 14 fixed, 1 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.

Summary

In the Linux kernel, the following vulnerability has been resolved: smb/client: handle overlapping allocated ranges in fallocate smb3_simple_fallocate_range() can skip holes when an allocated range returned by the server starts before the current fallocate offset. The skipped hole is not zero-filled, but fallocate still returns success. A later write to that hole may therefore fail with ENOSPC. The function queries allocated ranges so that it can preserve existing contents and write zeroes only into holes. However, the server may return a range that starts before the current fallocate offset. For example, assume the fallocate request is [100, 400) and the only allocated range returned by the server is [0, 200): Request: [100, 400) Server range: [ 0, 200) allocated Correct: [100, 200) allocated data, skip [200, 400) hole, zero-fill Current: [100, 300) skipped [300, 400) zero-filled afterwards The current code adds the full server range length, 200, to the current offset 100 and moves to 300. As a result, the hole in [200, 300) is skipped without being zero-filled. Fix this by advancing only over the part of the allocated range that overlaps the current fallocate offset. Ignore ranges that end before the current offset and reject ranges whose end offset overflows. This also prevents a malformed range length from causing an out-of-bounds zero-buffer read.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00514 44th percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.10.265, 5.13, 5.14 +7Red Hat: 4 advisoriesRed Hat: 14 fixed, 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux5.10.50 to before 5.10.265; 5.12.17 to before 5.13; 5.13.2 to before 5.145.10.265, 5.13, 5.14Patch availableCNA
LinuxLinux5.14 and later5.10.265, 5.15.216, 6.1.183, 6.6.148, 6.12.101, 6.18.42, 7.1.6, 7.2Patch availableCNA
  • Linux VendorLinux Affected 5.10.50 to before 5.10.265; 5.12.17 to before 5.13; 5.13.2 to before 5.14 Fixed in 5.10.265, 5.13, 5.14 Patch available CNA
  • Linux VendorLinux Affected 5.14 and later Fixed in 5.10.265, 5.15.216, 6.1.183, 6.6.148, 6.12.101, 6.18.42, 7.1.6, 7.2 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*——Linux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions — — ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 5.10.265, 5.13, 5.14
  • Fix · CNA Linux (Linux) Fixed in 5.10.265, 5.15.216, 6.1.183, 6.6.148, 6.12.101, 6.18.42, 7.1.6, 7.2

Red Hat 4 advisories

  • RHSA-2026:57252 Released 2026-08-20 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.41.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.41.1.el9_8, kernel-64k-devel-5.14.0-687.41.1.el9_8 +12
    • Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.41.1.el9_8, kernel-64k-5.14.0-687.41.1.el9_8, kernel-64k-core-5.14.0-687.41.1.el9_8 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.41.1.el9_8, libperf-5.14.0-687.41.1.el9_8
    • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.41.1.el9_8, kernel-rt-64k-5.14.0-687.41.1.el9_8, kernel-rt-64k-core-5.14.0-687.41.1.el9_8 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.41.1.el9_8, kernel-rt-core-5.14.0-687.41.1.el9_8, kernel-rt-debug-5.14.0-687.41.1.el9_8 +9
  • RHSA-2026:57251 Released 2026-08-20 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.49.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.49.1.el10_2, kernel-64k-devel-6.12.0-211.49.1.el10_2 +12
    • Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-211.49.1.el10_2, kernel-64k-6.12.0-211.49.1.el10_2, kernel-64k-core-6.12.0-211.49.1.el10_2 +29
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.49.1.el10_2, libperf-6.12.0-211.49.1.el10_2
    • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-211.49.1.el10_2, kernel-rt-64k-6.12.0-211.49.1.el10_2, kernel-rt-64k-core-6.12.0-211.49.1.el10_2 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-211.49.1.el10_2, kernel-rt-core-6.12.0-211.49.1.el10_2, kernel-rt-debug-6.12.0-211.49.1.el10_2 +9
  • RHSA-2026:57253 Released 2026-08-20 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-553.157.1.el8_10, kernel-4.18.0-553.157.1.el8_10, kernel-abi-stablelists-4.18.0-553.157.1.el8_10 +19
    • Red Hat Enterprise Linux CRB (v. 8) kernel-tools-libs-devel-4.18.0-553.157.1.el8_10
Show 1 more Red Hat advisories
  • RHSA-2026:57254 Released 2026-08-20 · Red Hat rating Important
    kernel-rt security, bug fix, and enhancement update
    • Red Hat Enterprise Linux NFV (v. 8) kernel-rt-4.18.0-553.157.1.rt7.498.el8_10, kernel-rt-core-4.18.0-553.157.1.rt7.498.el8_10, kernel-rt-debug-4.18.0-553.157.1.rt7.498.el8_10 +9
    • Red Hat Enterprise Linux RT (v. 8) kernel-rt-4.18.0-553.157.1.rt7.498.el8_10, kernel-rt-core-4.18.0-553.157.1.rt7.498.el8_10, kernel-rt-debug-4.18.0-553.157.1.rt7.498.el8_10 +7

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 9AffectedNo fix yet
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:57251
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:57252
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2026:57251
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2026:57253
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2026:57252
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2026:57253
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:57251
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:57252
Red Hat Enterprise Linux NFV (v. 8)Fixed RHSA-2026:57254
Red Hat Enterprise Linux RT (v. 8)Fixed RHSA-2026:57254
Red Hat Enterprise Linux Real Time (v. 10)Fixed RHSA-2026:57251
Red Hat Enterprise Linux Real Time (v. 9)Fixed RHSA-2026:57252
Red Hat Enterprise Linux Real Time for NFV (v. 10)Fixed RHSA-2026:57251
Red Hat Enterprise Linux Real Time for NFV (v. 9)Fixed RHSA-2026:57252
Not affected: 2 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-68388
  2. 2026-10-03 Alias added: GHSA-h6fv-x4pg-r56c
  3. 2026-10-16 CISA SSVC decision points changed
  4. 2026-10-20 Weakness changed · CISA ADP

References

Other 8

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2021-02452 Incorrect authorization in Ubuntu linux kernel 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
See all 21741 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences