CVE-2026-68171
kernel: Linux kernel (arm64): Security bypass due to stale syscall argument in ptrace and seccomp
Published Aug 10, 2026
CVSS 3.1 · 8.2 High
EPSS n/a
KEV · Not listed
Description
This CVE ID has been rejected or withdrawn by its CVE Numbering Authority.
Affected Products
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CVE record
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NVD configurations
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Red Hat packages
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OpenCVE enrichment
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No data available yet.
Remediation
Tracking
Advisories
Metrics
No CVSS v4.0
Attack Vector Local
Attack Complexity Low
Privileges Required High
Scope Changed
Confidentiality Impact High
Integrity Impact High
Availability Impact High
User Interaction None
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
No EPSS score available.
Key SSVC decision points have not yet been added.
References
History
Aug 12, 2026 12:15 AM
Title updated. Weaknesses updated. Added references. Scoring metrics updated
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| Title | kernel: Linux kernel (arm64): Security bypass due to stale syscall argument in ptrace and seccomp | |
| Weaknesses | CWE-807 | |
| References |
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| Metrics |
threat_severity
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cvssV3_1
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Aug 11, 2026 2:30 AM
Description updated. Title updated. Affected versions updated. References updated
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: arm64: syscall: Ensure saved x0 is kept in-sync with tracer updates When seccomp support was originally added to arm64 in a1ae65b21941 ("arm64: add seccomp support"), seccomp was erroneously called _before_ the ptrace syscall-enter-stop and therefore the tracer could trivially manipulate the syscall register state after the seccomp check had passed. This was subsequently fixed in a5cd110cb836 ("arm64/ptrace: run seccomp after ptrace") by moving the seccomp check after the tracer has run. Unfortunately, a decade later, that fix has been reported to be incomplete. On arm64, both the first argument to a syscall and its eventual return value are allocated to register x0. In order to facilitate syscall restarting and querying of syscall arguments on the syscall exit path, the original value of x0 is stashed in 'struct pt_regs::orig_x0' early during the syscall entry path and is returned for the first argument by syscall_get_arguments(). Unlike 32-bit Arm, this stashed value is not directly exposed via ptrace() and so changes to register x0 made by the tracer on a syscall-enter-stop are not reflected in 'orig_x0'. This means that seccomp, syscall tracepoints and audit can observe a stale value for the register compared to the argument that will be observed by the actual syscall. Re-sync 'orig_x0' from x0 on the syscall entry path following a potential ptrace stop (i.e. PTRACE_EVENTMSG_SYSCALL_ENTRY or SECCOMP_RET_TRACE). This behaviour is limited to native tasks (because compat tasks expose 'orig_r0' to ptrace) where the syscall is not being skipped (because x0 is updated to hold the return value of -ENOSYS in that case). | This CVE ID has been rejected or withdrawn by its CVE Numbering Authority. |
| Title | arm64: syscall: Ensure saved x0 is kept in-sync with tracer updates | |
| CPEs | ||
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Aug 10, 2026 2:15 PM
Weaknesses updated
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-20 |
Aug 10, 2026 12:30 PM
Description updated. Title updated. First appearance in the feed. Affected versions updated. Affected vendors updated. Added references
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: arm64: syscall: Ensure saved x0 is kept in-sync with tracer updates When seccomp support was originally added to arm64 in a1ae65b21941 ("arm64: add seccomp support"), seccomp was erroneously called _before_ the ptrace syscall-enter-stop and therefore the tracer could trivially manipulate the syscall register state after the seccomp check had passed. This was subsequently fixed in a5cd110cb836 ("arm64/ptrace: run seccomp after ptrace") by moving the seccomp check after the tracer has run. Unfortunately, a decade later, that fix has been reported to be incomplete. On arm64, both the first argument to a syscall and its eventual return value are allocated to register x0. In order to facilitate syscall restarting and querying of syscall arguments on the syscall exit path, the original value of x0 is stashed in 'struct pt_regs::orig_x0' early during the syscall entry path and is returned for the first argument by syscall_get_arguments(). Unlike 32-bit Arm, this stashed value is not directly exposed via ptrace() and so changes to register x0 made by the tracer on a syscall-enter-stop are not reflected in 'orig_x0'. This means that seccomp, syscall tracepoints and audit can observe a stale value for the register compared to the argument that will be observed by the actual syscall. Re-sync 'orig_x0' from x0 on the syscall entry path following a potential ptrace stop (i.e. PTRACE_EVENTMSG_SYSCALL_ENTRY or SECCOMP_RET_TRACE). This behaviour is limited to native tasks (because compat tasks expose 'orig_r0' to ptrace) where the syscall is not being skipped (because x0 is updated to hold the return value of -ENOSYS in that case). | |
| Title | arm64: syscall: Ensure saved x0 is kept in-sync with tracer updates | |
| First Time appeared |
Linux
Linux linux Kernel |
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| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
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| References |
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