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TI-2026-31247 Aliases CVE-2026-43067GHSA-845x-q62g-4v8p

ext4: handle wraparound when searching for blocks for indirect mapped blocks

Priority MEDIUM 49CWE-822Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 5 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-822 and the CVSS impact.

Summary

In the Linux kernel, the following vulnerability has been resolved: ext4: handle wraparound when searching for blocks for indirect mapped blocks Commit 4865c768b563 ("ext4: always allocate blocks only from groups inode can use") restricts what blocks will be allocated for indirect block based files to block numbers that fit within 32-bit block numbers. However, when using a review bot running on the latest Gemini LLM to check this commit when backporting into an LTS based kernel, it raised this concern: If ac->ac_g_ex.fe_group is >= ngroups (for instance, if the goal group was populated via stream allocation from s_mb_last_groups), then start will be >= ngroups. Does this allow allocating blocks beyond the 32-bit limit for indirect block mapped files? The commit message mentions that ext4_mb_scan_groups_linear() takes care to not select unsupported groups. However, its loop uses group = *start, and the very first iteration will call ext4_mb_scan_group() with this unsupported group because next_linear_group() is only called at the end of the iteration. After reviewing the code paths involved and considering the LLM review, I determined that this can happen when there is a file system where some files/directories are extent-mapped and others are indirect-block mapped. To address this, add a safety clamp in ext4_mb_scan_groups().

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00504 43rd percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.16, 6.1.168, 6.6.134 +3Red Hat: 5 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
LinuxLinux5.15.203 to before 5.165.16Patch availableCNA
LinuxLinux6.1.167 to before 6.1.168; 6.6.130 to before 6.6.134; 6.12.77 to before 6.12.80; 6.18.14 to before 6.18.21; 6.19.4 to before 6.19.116.1.168, 6.6.134, 6.12.80, 6.18.21, 6.19.11Patch availableCNA
  • Linux VendorLinux Affected 5.15.203 to before 5.16 Fixed in 5.16 Patch available CNA
  • Linux VendorLinux Affected 6.1.167 to before 6.1.168; 6.6.130 to before 6.6.134; 6.12.77 to before 6.12.80; 6.18.14 to before 6.18.21; 6.19.4 to before 6.19.11 Fixed in 6.1.168, 6.6.134, 6.12.80, 6.18.21, 6.19.11 Patch available CNA

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*5.15.203 to before 5.16; 6.6.130 to before 6.6.134; 6.12.77 to before 6.12.80; 6.18.14 to before 6.18.21; 6.19.4 to before 6.19.11VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.1.167:*:*:*:*:*:*:*6.1.167VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 5.15.203 to before 5.16; 6.6.130 to before 6.6.134; 6.12.77 to before 6.12.80; 6.18.14 to before 6.18.21; 6.19.4 to before 6.19.11 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.1.167:*:*:*:*:*:*:* Versions 6.1.167 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 5.16
  • Fix · CNA Linux (Linux) Fixed in 6.1.168, 6.6.134, 6.12.80, 6.18.21, 6.19.11

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Red Hat Enterprise Linux 10AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 8AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 9AffectedNo fix yet: Fix deferred

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-43067
  2. 2026-10-03 Alias added: GHSA-845x-q62g-4v8p
  3. 2026-10-16 CISA SSVC decision points changed
  4. 2026-10-19 Weakness changed · CISA ADP
  5. 2026-10-25 EPSS moved to the below the 50th percentile

References

Patch 6

  • 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-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
See all 15278 →

Sources

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