CVE-2019-15794 | Date: (C)2020-04-24 (M)2024-06-11 |
Overlayfs in the Linux kernel and shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series, both replace vma->vm_file in their mmap handlers. On error the original value is not restored, and the reference is put for the file to which vm_file points. On upstream kernels this is not an issue, as no callers dereference vm_file following after call_mmap() returns an error. However, the aufs patchs change mmap_region() to replace the fput() using a local variable with vma_fput(), which will fput() vm_file, leading to a refcount underflow.
CVSS Score and Metrics +CVSS Score and Metrics -CVSS V3 Severity: | CVSS V2 Severity: |
CVSS Score : 6.7 | CVSS Score : 7.2 |
Exploit Score: 0.8 | Exploit Score: 3.9 |
Impact Score: 5.9 | Impact Score: 10.0 |
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CVSS V3 Metrics: | CVSS V2 Metrics: |
Attack Vector: LOCAL | Access Vector: LOCAL |
Attack Complexity: LOW | Access Complexity: LOW |
Privileges Required: HIGH | Authentication: NONE |
User Interaction: NONE | Confidentiality: COMPLETE |
Scope: UNCHANGED | Integrity: COMPLETE |
Confidentiality: HIGH | Availability: COMPLETE |
Integrity: HIGH | |
Availability: HIGH | |
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