9p/xen: protect xen_9pfs_front_free against concurrent calls
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:00
CVE-2026-43249
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-43249
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "c15fe55d14b3b4ded5af2a3260877460a6ffb8ad",
"lessThan": "480aa6ffd4ac7036eea042047d0cca71bc2074bb",
"versionType": "git"
},
{
"status": "affected",
"version": "c15fe55d14b3b4ded5af2a3260877460a6ffb8ad",
"lessThan": "a5d00dff97118a32fcf5fec7a4c3f864c4620c4e",
"versionType": "git"
},
{
"status": "affected",
"version": "c15fe55d14b3b4ded5af2a3260877460a6ffb8ad",
"lessThan": "59e7707492576bdbfa8c1dbe7d90791df31e4773",
"versionType": "git"
},
{
"status": "affected",
"version": "c15fe55d14b3b4ded5af2a3260877460a6ffb8ad",
"lessThan": "bf841d43f7a33d75675ba7f4e214ac1c67913065",
"versionType": "git"
},
{
"status": "affected",
"version": "c15fe55d14b3b4ded5af2a3260877460a6ffb8ad",
"lessThan": "ce8ded2e61f47747e31eeefb44dc24a2160a7e32",
"versionType": "git"
},
{
"status": "affected",
"version": "be03c4fe72384366fd4077a70966bd3b8fc49013",
"versionType": "git"
},
{
"status": "affected",
"version": "1ab4de11232e83b875b071aa44d1155634ca8a1e",
"versionType": "git"
},
{
"status": "affected",
"version": "7cc9dbae8a5f73bd555130384ea256018d28f283",
"versionType": "git"
},
{
"status": "affected",
"version": "3e0359f151ac151abe3fa71040e450ed69cb824b",
"versionType": "git"
},
{
"status": "affected",
"version": "8d3fc907d060c4fb33203e616a395a22083b6566",
"versionType": "git"
},
{
"status": "affected",
"version": "4f0e9244770f5b75a16d8c0929063cd336926764",
"versionType": "git"
},
{
"status": "affected",
"version": "5f6a8974e9ef317fe63f88bab1f33070195dd147",
"versionType": "git"
},
{
"status": "affected",
"version": "4.14.308",
"lessThan": "4.15",
"versionType": "semver"
},
{
"status": "affected",
"version": "4.19.276",
"lessThan": "4.20",
"versionType": "semver"
},
{
"status": "affected",
"version": "5.4.235",
"lessThan": "5.5",
"versionType": "semver"
},
{
"status": "affected",
"version": "5.10.173",
"lessThan": "5.11",
"versionType": "semver"
},
{
"status": "affected",
"version": "5.15.100",
"lessThan": "5.16",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.1.18",
"lessThan": "6.2",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.2.5",
"lessThan": "6.3",
"versionType": "semver"
}
],
"programFiles": [
"net/9p/trans_xen.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.3"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.3",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.75",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.16",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "6.19.6",
"versionType": "semver",
"lessThanOrEqual": "6.19.*"
},
{
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/9p/trans_xen.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-43249
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #46277 · Revision 1
- Added to Heist Feed
- Publisher date