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TI-2026-31428 Aliases CVE-2026-43249GHSA-387w-9mx8-66cc

9p/xen: protect xen_9pfs_front_free against concurrent calls

Priority LOW 38CWE-415Published · Updated

Key facts

Attack vector
Adjacent network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-415 and the CVSS impact.

Summary

In the Linux kernel, the following vulnerability has been resolved: 9p/xen: protect xen_9pfs_front_free against concurrent calls The xenwatch thread can race with other back-end change notifications and call xen_9pfs_front_free() twice, hitting the observed general protection fault due to a double-free. Guard the teardown path so only one caller can release the front-end state at a time, preventing the crash. This is a fix for the following double-free: [ 27.052347] Oops: general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6b6b: 0000 [#1] SMP DEBUG_PAGEALLOC NOPTI [ 27.052357] CPU: 0 UID: 0 PID: 32 Comm: xenwatch Not tainted 6.18.0-02087-g51ab33fc0a8b-dirty #60 PREEMPT(none) [ 27.052363] RIP: e030:xen_9pfs_front_free+0x1d/0x150 [ 27.052368] Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 41 55 41 54 55 48 89 fd 48 c7 c7 48 d0 92 85 53 e8 cb cb 05 00 48 8b 45 08 48 8b 55 00 <48> 3b 28 0f 85 f9 28 35 fe 48 3b 6a 08 0f 85 ef 28 35 fe 48 89 42 [ 27.052377] RSP: e02b:ffffc9004016fdd0 EFLAGS: 00010246 [ 27.052381] RAX: 6b6b6b6b6b6b6b6b RBX: ffff88800d66e400 RCX: 0000000000000000 [ 27.052385] RDX: 6b6b6b6b6b6b6b6b RSI: 0000000000000000 RDI: 0000000000000000 [ 27.052389] RBP: ffff88800a887040 R08: 0000000000000000 R09: 0000000000000000 [ 27.052393] R10: 0000000000000000 R11: 0000000000000000 R12: ffff888009e46b68 [ 27.052397] R13: 0000000000000200 R14: 0000000000000000 R15: ffff88800a887040 [ 27.052404] FS: 0000000000000000(0000) GS:ffff88808ca57000(0000) knlGS:0000000000000000 [ 27.052408] CS: e030 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 27.052412] CR2: 00007f9714004360 CR3: 0000000004834000 CR4: 0000000000050660 [ 27.052418] Call Trace: [ 27.052420] <TASK> [ 27.052422] xen_9pfs_front_changed+0x5d5/0x720 [ 27.052426] ? xenbus_otherend_changed+0x72/0x140 [ 27.052430] ? __pfx_xenwatch_thread+0x10/0x10 [ 27.052434] xenwatch_thread+0x94/0x1c0 [ 27.052438] ? __pfx_autoremove_wake_function+0x10/0x10 [ 27.052442] kthread+0xf8/0x240 [ 27.052445] ? __pfx_kthread+0x10/0x10 [ 27.052449] ? __pfx_kthread+0x10/0x10 [ 27.052452] ret_from_fork+0x16b/0x1a0 [ 27.052456] ? __pfx_kthread+0x10/0x10 [ 27.052459] ret_from_fork_asm+0x1a/0x30 [ 27.052463] </TASK> [ 27.052465] Modules linked in: [ 27.052471] ---[ end trace 0000000000000000 ]---

Why it matters now

EPSS 0.00317 24th percentileScored 2026-11-07
Fix Fixed Linux (Linux): 6.1.191, 4.15, 4.20 +9

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux6.1.18 to before 6.1.191; 4.14.308 to before 4.15; 4.19.276 to before 4.20; 5.4.235 to before 5.5; 5.10.173 to before 5.11; 5.15.100 to before 5.16; 6.2.5 to before 6.36.1.191, 4.15, 4.20, 5.5, 5.11, 5.16, 6.3Patch availableCNA
LinuxLinux6.3 and later6.1.191, 6.6.160, 6.12.75, 6.18.16, 6.19.6, 7.0Patch availableCNA
  • Linux VendorLinux Affected 6.1.18 to before 6.1.191; 4.14.308 to before 4.15; 4.19.276 to before 4.20; 5.4.235 to before 5.5; 5.10.173 to before 5.11; 5.15.100 to before 5.16; 6.2.5 to before 6.3 Fixed in 6.1.191, 4.15, 4.20, 5.5, 5.11, 5.16, 6.3 Patch available CNA
  • Linux VendorLinux Affected 6.3 and later Fixed in 6.1.191, 6.6.160, 6.12.75, 6.18.16, 6.19.6, 7.0 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*4.14.308 to before 6.12.75; 6.13 to before 6.18.16; 6.19 to before 6.19.6VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 4.14.308 to before 6.12.75; 6.13 to before 6.18.16; 6.19 to before 6.19.6 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 6.1.191, 4.15, 4.20, 5.5, 5.11, 5.16, 6.3
  • Fix · CNA Linux (Linux) Fixed in 6.1.191, 6.6.160, 6.12.75, 6.18.16, 6.19.6, 7.0

Vendor assessments

Red Hat

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

Not affected: 5 products
  • Red Hat Enterprise Linux 10
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-43249
  2. 2026-10-03 Alias added: GHSA-387w-9mx8-66cc
  3. 2026-10-20 Affected versions changed · Red Hat
  4. 2026-10-21 Fix available: Linux/Linux@480aa6ffd4ac7036eea042047d0cca71bc2074bb, Linux/[email protected] · CNA
  5. 2026-10-21 1 new reference · CNA
  6. 2026-10-30 Fix available: Linux/Linux@056709e2c6f121548df108a9fef2d1430b233e56, Linux/[email protected] · CNA
  7. 2026-10-30 1 new reference · CNA

References

Patch 4

Other 2

  • 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