Bug 2541022 (CVE-2026-97560)

Summary: CVE-2026-97560 kernel: smb: client: fix one-byte OOB read in smb2_parse_native_symlink()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in the Linux kernel's SMB (Server Message Block) client. When parsing a share-root relative native symbolic link, an incorrect length calculation causes the client to read past the end of the allocated buffer in the smb2_parse_native_symlink function. A malicious server or attacker providing crafted SMB responses can exploit this issue to trigger a Denial of Service (DoS) via a kernel crash or potentially expose sensitive kernel memory.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-25 10:41:59 UTC 
In the Linux kernel, the following vulnerability has been resolved:

smb: client: fix one-byte OOB read in smb2_parse_native_symlink()

When parsing a share-root relative native symlink, memcpy copies
smb_target+1 (skipping the leading separator) but uses
strlen(smb_target)+1 as the length, reading one byte past the
allocated buffer.

This fixes the following KASAN splat when accessing an SMB symlink
with a target of '\a\b':

  BUG: KASAN: slab-out-of-bounds in smb2_parse_native_symlink+0x4f5/0xca0
  Read of size 5 at addr ffff88800878fe21 by task netfsfuzz-execu/1
  CPU: 1 UID: 0 PID: 1 Comm: netfsfuzz-execu Tainted: G N
  7.2.0-11943-g2709dd5ae32f-dirty #1 PREEMPT(lazy)
  Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix,
  1996)
  Call Trace:
   <TASK>
   dump_stack_lvl+0x7b/0xa0
   print_report+0xd0/0x630
   kasan_report+0xe5/0x120
   kasan_check_range+0x105/0x1b0
   __asan_memcpy+0x23/0x60
   smb2_parse_native_symlink+0x4f5/0xca0
   parse_reparse_point+0x68a/0x1530
   reparse_info_to_fattr+0x752/0xa20
   cifs_get_fattr+0x873/0x15b0
   cifs_get_inode_info+0xc0/0x310
   cifs_lookup+0x308/0xa70
   __lookup_slow+0x122/0x2b0
   lookup_slow+0x50/0x70
   path_lookupat+0x525/0xaf0
   filename_lookup+0x1f2/0x550
   vfs_statx+0xd1/0x1a0
   vfs_fstatat+0x65/0xc0
   __do_sys_newfstatat+0x9a/0x120
   do_syscall_64+0xdd/0x4a0
   entry_SYSCALL_64_after_hwframe+0x77/0x7f
Comment 1 gkamathe 2026-09-29 02:52:04 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-97560.mbox