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CVE-2019-15793

HIGHCVSS 8.8/10EPSS 0.69%

Last modified

CVE-2019-15793 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. In shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series, several locations which shift ids translate user/group ids before performing operations in the lower filesystem were translating them into init_user_ns, whereas they should have been translated into the s_user_ns for the lower filesystem. This resulted in using ids other than the intended ones in the lower fs, which likely did not map into the shifts s_user_ns. EPSS estimates a 0.69% chance of exploitation in the next 30 days.

Description

In shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series, several locations which shift ids translate user/group ids before performing operations in the lower filesystem were translating them into init_user_ns, whereas they should have been translated into the s_user_ns for the lower filesystem. This resulted in using ids other than the intended ones in the lower fs, which likely did not map into the shifts s_user_ns. A local attacker could use this to possibly bypass discretionary access control permissions.

Metrics

CVSS 3.1
8.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

EPSS Probability
0.69%

47.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
LinuxLinux Kernel5.0
LinuxLinux Kernel5.3
CanonicalUbuntu Linux18.04
CanonicalUbuntu Linux19.04

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2019-15793?
In shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series, several locations which shift ids translate user/group ids before performing operations in the lower filesystem were translating them into init_user_ns, whereas they should have been translated into the s_user_ns for the lower filesystem. This resulted in using ids other than the intended ones in the lower fs, which likely did not map into the shifts s_user_ns. A local attacker could use this to possibly bypass discretionary access control permissions.
How severe is CVE-2019-15793?
CVE-2019-15793 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 0.69% probability of exploitation in the next 30 days.
How do I fix CVE-2019-15793?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2019-15793?

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Source: NVD / NIST