CVE-2026-432499p/xen: protect xen_9pfs_front_free against concurrent calls
- 8.8HighCVSS base score
- 0.32%Exploitation in 30 daysEPSS · top 75% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
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 ]---
Timeline
ID reserved
By Linux
- 5 days later
· 5 days later
Published
- 6 months later
· 6 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High8.8 | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Modified | 3.1 | High8.8 | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.32% · top 75% of all CVEs (15 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.8.
Affected products
- affected 4f0e9244770f5b75a16d8c0929063cd336926764 – < 056709e2c6f121548df108a9fef2d1430b233e56
- affected c15fe55d14b3b4ded5af2a3260877460a6ffb8ad – < 480aa6ffd4ac7036eea042047d0cca71bc2074bb
- affected c15fe55d14b3b4ded5af2a3260877460a6ffb8ad – < a5d00dff97118a32fcf5fec7a4c3f864c4620c4e
- affected c15fe55d14b3b4ded5af2a3260877460a6ffb8ad – < 59e7707492576bdbfa8c1dbe7d90791df31e4773
- affected c15fe55d14b3b4ded5af2a3260877460a6ffb8ad – < bf841d43f7a33d75675ba7f4e214ac1c67913065
- affected c15fe55d14b3b4ded5af2a3260877460a6ffb8ad – < ce8ded2e61f47747e31eeefb44dc24a2160a7e32
- affected be03c4fe72384366fd4077a70966bd3b8fc49013
- affected 1ab4de11232e83b875b071aa44d1155634ca8a1e
- affected 7cc9dbae8a5f73bd555130384ea256018d28f283
- affected 3e0359f151ac151abe3fa71040e450ed69cb824b
- affected 8d3fc907d060c4fb33203e616a395a22083b6566
- affected 5f6a8974e9ef317fe63f88bab1f33070195dd147
- affected 6.1.18 – < 6.1.191
- affected 4.14.308 – < 4.15
- affected 4.19.276 – < 4.20
- affected 5.4.235 – < 5.5
- affected 5.10.173 – < 5.11
- affected 5.15.100 – < 5.16
- affected 6.2.5 – < 6.3
- affected 6.3
- unaffected < 6.3
- unaffected 6.1.191 – ≤ 6.1.*
- unaffected 6.6.160 – ≤ 6.6.*
- unaffected 6.12.75 – ≤ 6.12.*
- unaffected 6.18.16 – ≤ 6.18.*
- unaffected 6.19.6 – ≤ 6.19.*
- unaffected 7.0 – ≤ *
References
References6
- https://git.kernel.org/stable/c/056709e2c6f121548df108a9fef2d1430b233e56 (opens in a new tab)
- https://git.kernel.org/stable/c/480aa6ffd4ac7036eea042047d0cca71bc2074bb (opens in a new tab)
- https://git.kernel.org/stable/c/a5d00dff97118a32fcf5fec7a4c3f864c4620c4e (opens in a new tab)
- https://git.kernel.org/stable/c/59e7707492576bdbfa8c1dbe7d90791df31e4773 (opens in a new tab)
- https://git.kernel.org/stable/c/bf841d43f7a33d75675ba7f4e214ac1c67913065 (opens in a new tab)
- https://git.kernel.org/stable/c/ce8ded2e61f47747e31eeefb44dc24a2160a7e32 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-27808 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-43249)Record last updated .