mptcp: pm: userspace: fix use-after-free in get_local_id

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-68169
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-10 13:20:03 UTC
Updated2026-08-17 05:18:17 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: mptcp: pm: userspace: fix use-after-free in get_local_id In mptcp_pm_userspace_get_local_id(), the address entry is looked up under spinlock, but its id is read after dropping the lock. A concurrent deletion can free the entry between the unlock and the read, leading to UAF. The race window is narrow. It was reproduced only with a locally constructed stress test that repeatedly overlaps an MP_JOIN SYN with a MPTCP_PM_CMD_SUBFLOW_DESTROY request. However, the KASAN report below confirms that the race is reachable: [ 666.319376] BUG: KASAN: slab-use-after-free in mptcp_userspace_pm_get_local_id+0x1dc/0x1f0 [ 666.319386] Read of size 1 at addr ffff888124845610 by task swapper/0/0 ... [ 666.319401] Call Trace: [ 666.319405] <IRQ> [ 666.319408] dump_stack_lvl+0x53/0x70 [ 666.319412] print_address_description.constprop.0+0x2c/0x3b0 [ 666.319418] print_report+0xbe/0x2b0 [ 666.319421] ? mptcp_userspace_pm_get_local_id+0x1dc/0x1f0 [ 666.319423] kasan_report+0xce/0x100 [ 666.319426] ? mptcp_userspace_pm_get_local_id+0x1dc/0x1f0 [ 666.319429] mptcp_userspace_pm_get_local_id+0x1dc/0x1f0 [ 666.319433] mptcp_pm_get_local_id+0x371/0x440 ... [ 666.319821] Allocated by task 45539: [ 666.319844] kasan_save_stack+0x33/0x60 [ 666.319855] kasan_save_track+0x14/0x30 [ 666.319858] __kasan_kmalloc+0x8f/0xa0 [ 666.319863] __kmalloc_noprof+0x1e7/0x520 [ 666.319867] sock_kmalloc+0xdf/0x130 [ 666.319885] sock_kmemdup+0x1b/0x40 [ 666.319888] mptcp_userspace_pm_append_new_local_addr+0x261/0x500 [ 666.319910] mptcp_pm_nl_announce_doit+0x16a/0x610 ... [ 666.319967] Freed by task 45560: [ 666.319988] kasan_save_stack+0x33/0x60 [ 666.319991] kasan_save_track+0x14/0x30 [ 666.319994] kasan_save_free_info+0x3b/0x60 [ 666.319998] __kasan_slab_free+0x43/0x70 [ 666.320000] kfree+0x166/0x440 [ 666.320003] sock_kfree_s+0x1d/0x50 [ 666.320007] mptcp_userspace_pm_delete_local_addr.isra.0+0x157/0x200 [ 666.320011] mptcp_pm_nl_subflow_destroy_doit+0x51d/0xea0 Fix by copying the id into a local variable while still holding the lock, and use -1 as a "not found" sentinel.

Risk And Classification

EPSS: 0.002000000 probability, percentile 0.101670000 (date 2026-08-17)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected ed34dfa19ddbd1e4c85a73636f8cba0211025ea4 d2c3760b45f2f481a4dd4c5adef4a29dfabd948f git Not specified
CNA Linux Linux affected f012d796a6de662692159c539689e47e662853a8 31ce5af66891f79998fb2e8b8df08e3c98fd72e3 git Not specified
CNA Linux Linux affected f012d796a6de662692159c539689e47e662853a8 d64f6c02495f3fad674038cfa7ec049671b59e7b git Not specified
CNA Linux Linux affected f012d796a6de662692159c539689e47e662853a8 40dde4b5d98279471a70e5c8bb713182738c00d9 git Not specified
CNA Linux Linux affected f012d796a6de662692159c539689e47e662853a8 9bc6d5e4ca9f3cbb41d43400b3a31cb0403796c9 git Not specified
CNA Linux Linux affected e373bfc8ec3d6496ec7e11dd7f4d087a44b1009a git Not specified
CNA Linux Linux affected 005a3ad289eb604216dcaa03646de36cb08624a0 git Not specified
CNA Linux Linux affected 6.6.18 6.6.151 semver Not specified
CNA Linux Linux affected 6.1.79 6.2 semver Not specified
CNA Linux Linux affected 6.7.6 6.8 semver Not specified
CNA Linux Linux affected 6.8 Not specified
CNA Linux Linux unaffected 6.8 semver Not specified
CNA Linux Linux unaffected 6.6.151 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.103 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.42 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.6 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/d2c3760b45f2f481a4dd4c5adef4a29dfabd948f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/31ce5af66891f79998fb2e8b8df08e3c98fd72e3 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/9bc6d5e4ca9f3cbb41d43400b3a31cb0403796c9 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/d64f6c02495f3fad674038cfa7ec049671b59e7b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/40dde4b5d98279471a70e5c8bb713182738c00d9 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

© CVE.report 2026

Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. It is the responsibility of user to evaluate the accuracy, completeness or usefulness of any information, opinion, advice or other content. EACH USER WILL BE SOLELY RESPONSIBLE FOR ANY consequences of his or her direct or indirect use of this web site. ALL WARRANTIES OF ANY KIND ARE EXPRESSLY DISCLAIMED. This site will NOT BE LIABLE FOR ANY DIRECT, INDIRECT or any other kind of loss.

CVE, CWE, and OVAL are registred trademarks of The MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. This site includes MITRE data granted under the following license.

Free CVE JSON API cve.report/api

CVE.report and Source URL Uptime Status status.cve.report