fkie_cve-2025-40341
Vulnerability from fkie_nvd
Published
2025-12-09 16:17
Modified
2025-12-09 18:36
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
futex: Don't leak robust_list pointer on exec race
sys_get_robust_list() and compat_get_robust_list() use ptrace_may_access()
to check if the calling task is allowed to access another task's
robust_list pointer. This check is racy against a concurrent exec() in the
target process.
During exec(), a task may transition from a non-privileged binary to a
privileged one (e.g., setuid binary) and its credentials/memory mappings
may change. If get_robust_list() performs ptrace_may_access() before
this transition, it may erroneously allow access to sensitive information
after the target becomes privileged.
A racy access allows an attacker to exploit a window during which
ptrace_may_access() passes before a target process transitions to a
privileged state via exec().
For example, consider a non-privileged task T that is about to execute a
setuid-root binary. An attacker task A calls get_robust_list(T) while T
is still unprivileged. Since ptrace_may_access() checks permissions
based on current credentials, it succeeds. However, if T begins exec
immediately afterwards, it becomes privileged and may change its memory
mappings. Because get_robust_list() proceeds to access T->robust_list
without synchronizing with exec() it may read user-space pointers from a
now-privileged process.
This violates the intended post-exec access restrictions and could
expose sensitive memory addresses or be used as a primitive in a larger
exploit chain. Consequently, the race can lead to unauthorized
disclosure of information across privilege boundaries and poses a
potential security risk.
Take a read lock on signal->exec_update_lock prior to invoking
ptrace_may_access() and accessing the robust_list/compat_robust_list.
This ensures that the target task's exec state remains stable during the
check, allowing for consistent and synchronized validation of
credentials.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfutex: Don\u0027t leak robust_list pointer on exec race\n\nsys_get_robust_list() and compat_get_robust_list() use ptrace_may_access()\nto check if the calling task is allowed to access another task\u0027s\nrobust_list pointer. This check is racy against a concurrent exec() in the\ntarget process.\n\nDuring exec(), a task may transition from a non-privileged binary to a\nprivileged one (e.g., setuid binary) and its credentials/memory mappings\nmay change. If get_robust_list() performs ptrace_may_access() before\nthis transition, it may erroneously allow access to sensitive information\nafter the target becomes privileged.\n\nA racy access allows an attacker to exploit a window during which\nptrace_may_access() passes before a target process transitions to a\nprivileged state via exec().\n\nFor example, consider a non-privileged task T that is about to execute a\nsetuid-root binary. An attacker task A calls get_robust_list(T) while T\nis still unprivileged. Since ptrace_may_access() checks permissions\nbased on current credentials, it succeeds. However, if T begins exec\nimmediately afterwards, it becomes privileged and may change its memory\nmappings. Because get_robust_list() proceeds to access T-\u003erobust_list\nwithout synchronizing with exec() it may read user-space pointers from a\nnow-privileged process.\n\nThis violates the intended post-exec access restrictions and could\nexpose sensitive memory addresses or be used as a primitive in a larger\nexploit chain. Consequently, the race can lead to unauthorized\ndisclosure of information across privilege boundaries and poses a\npotential security risk.\n\nTake a read lock on signal-\u003eexec_update_lock prior to invoking\nptrace_may_access() and accessing the robust_list/compat_robust_list.\nThis ensures that the target task\u0027s exec state remains stable during the\ncheck, allowing for consistent and synchronized validation of\ncredentials."
}
],
"id": "CVE-2025-40341",
"lastModified": "2025-12-09T18:36:53.557",
"metrics": {},
"published": "2025-12-09T16:17:44.387",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/3b4222494489f6d4b8705a496dab03384b7ca998"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/4aced32596ead1820b7dbd8e40d30b30dc1f3ad4"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/6511984d1aa1360181bcafb1ca75df7f291ef237"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/6b54082c3ed4dc9821cdf0edb17302355cc5bb45"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/b524455a51feb6013df3a5dba3160487b2e8e22a"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Awaiting Analysis"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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