NULL Pointer Dereference Affecting kernel package, versions *


Severity

Recommended
0.0
medium
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.16% (5th percentile)

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  • Snyk IDSNYK-RHEL10-KERNEL-22283152
  • published8 Nov 2026
  • disclosed7 Nov 2026

Introduced: 7 Nov 2026

NewCVE-2026-99274  (opens in a new tab)
CWE-476  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:10 kernel.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel package and not the kernel package as distributed by RHEL. See How to fix? for RHEL:10 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

smb: client: fix fiemap wild read on empty truncated response

smb3_fiemap() treats -E2BIG from SMB2_ioctl() as a truncated range blob and loops for the next chunk. If the server reports STATUS_BUFFER_OVERFLOW with OutputCount == 0, SMB2_ioctl() returns -E2BIG with out_data == NULL and out_data_len == 0, and the existing length checks accept the empty result. The loop then evaluates

next = out_data[num - 1].file_offset + ...

with num == 0, reading 16 bytes before NULL.

Reject a truncated range blob that contains no range, so the resume offset is never computed from an empty response. Also require the last range in a truncated blob to advance the resume offset without overflowing, and to stay within the requested range; a malicious or broken server could otherwise make no progress or underflow len and loop forever. Free the previous response buffer before retrying.

Reproduced on 6.6.87.2 with a malicious SMB2 server that answers FSCTL_QUERY_ALLOCATED_RANGES with STATUS_BUFFER_OVERFLOW and OutputCount == 0; an FS_IOC_FIEMAP ioctl on the mount oopses in cifs_fiemap() with CR2 = fffffffffffffff8. The code path is unchanged on mainline.

CVSS Base Scores

version 3.1