futex/pi: Reject cross-mm private futex owners
In the Linux kernel, the following vulnerability has been resolved: futex/pi: Reject cross-mm private futex owners A private futex key borrows the waiter's mm without taking an mm_users reference. Nevertheless, attach_to_pi_owner() currently accepts an owner from a different address space and copies the private key into the owner's PI state. When that owner exits, exit_pi_state_list() uses the saved key to find the hash bucket and acquires a reference to the waiter's private hash. If the last user of the waiter's mm exits concurrently, futex_hash_free() frees the hash while the owner still uses its bucket and reference. Prevent this by validating in attach_to_pi_owner() that, for private futexes, the owner mm and waiter mm are the same. Perform the check with the owner's pi_lock held and after validating owner::futex::state to serialize against a concurrent PI-state exit cleanup. [ tglx: Amended comment ]
CVE-2026-80778
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-2026-80778
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": "80367ad01d93ac781b0e1df246edaf006928002f",
"lessThan": "2b92e5562653b5293529f63b0300837d9dcedbd7",
"versionType": "git"
},
{
"status": "affected",
"version": "80367ad01d93ac781b0e1df246edaf006928002f",
"lessThan": "f7fb3e07752688842cbe0b85cf0d98c2fbf76b68",
"versionType": "git"
},
{
"status": "affected",
"version": "80367ad01d93ac781b0e1df246edaf006928002f",
"lessThan": "43b148d796aa338858792d0167cebdc12b8cb4b9",
"versionType": "git"
},
{
"status": "affected",
"version": "80367ad01d93ac781b0e1df246edaf006928002f",
"lessThan": "59b3732f95dda1fbd2234514d35f4fb6b5bb6d85",
"versionType": "git"
}
],
"programFiles": [
"kernel/futex/pi.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.16"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.16",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.18.47",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.11",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2.1",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"kernel/futex/pi.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-80778
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #34798 · Revision 1
- Added to Heist Feed
- Publisher date