pidfd: hold exec_update_lock around namespace ioctl
In the Linux kernel, the following vulnerability has been resolved: pidfd: hold exec_update_lock around namespace ioctl The PIDFD_GET_*_NAMESPACE ioctls in pidfd_ioctl() perform a filesystem credentials ptrace access check before handing out a namespace file descriptor. The accompanying comment states that the code "mirrors nsfs behavior", but, unlike the corresponding procfs paths, it does so without holding the target task's exec_update_lock. proc_ns_get_link() and proc_ns_readlink() both take exec_update_lock for reading around the ptrace check and the namespace lookup, so that the credentials used for the access decision match those of the task when its namespace is read. Without it, a caller can pass the check against the target's old credentials and then read the namespace after the target has execve()'d a setuid binary and committed new credentials -- accessing namespace information it should have been denied. Hold exec_update_lock for reading around the ptrace check and the namespace lookup so that pidfd truly mirrors nsfs behavior, as the comment already claims. open_namespace() itself runs outside the lock: once a namespace reference is obtained it carries its own refcount and is opened with the caller's own credentials, so a concurrent execve() on the target can no longer affect the outcome.
CVE-2026-89766
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-2026-89766
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": "5b08bd408534bfb3a7cf5778da5b27d4e4fffe12",
"lessThan": "bac2f1913a216677c2c220d7bb352dd0330065ca",
"versionType": "git"
},
{
"status": "affected",
"version": "5b08bd408534bfb3a7cf5778da5b27d4e4fffe12",
"lessThan": "cf24ce48d60225fdbee68ed2058763a1fd172ff3",
"versionType": "git"
},
{
"status": "affected",
"version": "5b08bd408534bfb3a7cf5778da5b27d4e4fffe12",
"lessThan": "e89318aa8629969e86548b05e7c19283af3f0efb",
"versionType": "git"
},
{
"status": "affected",
"version": "5b08bd408534bfb3a7cf5778da5b27d4e4fffe12",
"lessThan": "9688a46802939da28f00cb40e8129615d5d4af39",
"versionType": "git"
}
],
"programFiles": [
"fs/pidfs.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.11"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.11",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.12.112",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.51",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.4",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/pidfs.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-89766
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #35234 · Revision 1
- Added to Heist Feed
- Publisher date