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CVE-2024-36943

MEDIUMCVSS 4.7/10EPSS 0.18%

Last modified

CVE-2024-36943 is a medium-severity vulnerability rated 4.7/10 on the CVSS scale. In the Linux kernel, the following vulnerability has been resolved: fs/proc/task_mmu: fix loss of young/dirty bits during pagemap scan make_uffd_wp_pte() was previously doing: pte = ptep_get(ptep); ptep_modify_prot_start(ptep); pte = pte_mkuffd_wp(pte); ptep_modify_prot_commit(ptep, pte); But if another thread accessed or dirtied the pte between the first 2 calls, this could lead to loss of that information. Since ptep_modify_prot_start() gets and clears atomically, the following is the correct pattern and prevents any possible race. EPSS estimates a 0.18% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: fs/proc/task_mmu: fix loss of young/dirty bits during pagemap scan make_uffd_wp_pte() was previously doing: pte = ptep_get(ptep); ptep_modify_prot_start(ptep); pte = pte_mkuffd_wp(pte); ptep_modify_prot_commit(ptep, pte); But if another thread accessed or dirtied the pte between the first 2 calls, this could lead to loss of that information. Since ptep_modify_prot_start() gets and clears atomically, the following is the correct pattern and prevents any possible race. Any access after the first call would see an invalid pte and cause a fault: pte = ptep_modify_prot_start(ptep); pte = pte_mkuffd_wp(pte); ptep_modify_prot_commit(ptep, pte);

Metrics

CVSS 3.1
4.7/10

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

EPSS Probability
0.18%

7.4th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

VendorProductVersionsUpdate
LinuxLinux Kernel>= 6.7, < 6.8.10—
LinuxLinux Kernel6.9Rc1

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2024-36943?
In the Linux kernel, the following vulnerability has been resolved: fs/proc/task_mmu: fix loss of young/dirty bits during pagemap scan make_uffd_wp_pte() was previously doing: pte = ptep_get(ptep); ptep_modify_prot_start(ptep); pte = pte_mkuffd_wp(pte); ptep_modify_prot_commit(ptep, pte); But if another thread accessed or dirtied the pte between the first 2 calls, this could lead to loss of that information. Since ptep_modify_prot_start() gets and clears atomically, the following is the correct pattern and prevents any possible race. Any access after the first call would see an invalid pte and cause a fault: pte = ptep_modify_prot_start(ptep); pte = pte_mkuffd_wp(pte); ptep_modify_prot_commit(ptep, pte);
How severe is CVE-2024-36943?
CVE-2024-36943 has a CVSS score of 4.7/10 (MEDIUM severity). The EPSS model estimates a 0.18% probability of exploitation in the next 30 days.
How do I fix CVE-2024-36943?
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-2024-36943?

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Source: NVD / NIST