Microsoft security update for CVE-2025-21919
🔗 CVE IDs covered (1)
📋 Microsoft's advisory
EchelonGraph does not copy Microsoft's advisory page: its FAQ and remediation text are not shown here. Read the advisory on https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21919. This page also shows what EchelonGraph holds for CVE-2025-21919, with the description from its CVE record, which the CVE Numbering Authority that assigned the CVE wrote: for a CVE Microsoft assigned, often in the words of Microsoft's own advisory.
🎯 Affected products5
- azl3 kernel 6.6.82.1-1 on Azure Linux 3.0
- azl3 kernel 6.6.85.1-2 on Azure Linux 3.0
- cbl2 kernel 5.15.176.3-3 on CBL Mariner 2.0
- cbl2 kernel 5.15.176.3-3 on CBL-Mariner 2.0
- cbl2 kernel 5.15.180.1-1 on CBL Mariner 2.0
✅ Updates Microsoft lists: 2 updates
2 rows: one per KB article or update, update type and fixed build. Their details are on Microsoft's advisory.
| KB article | Update | Fixed build |
|---|---|---|
| — | Security Update | 5.15.180.1-1 |
| — | Security Update | 6.6.85.1-2 |
🧭 EchelonGraph on CVE-2025-21919
- EchelonGraph score
- 7.8 HIGH
- CISA KEV
- Not listed
- Fix status
- A fix is available — apply it.
Description from the CVE record (CVE.org), as published by its numbering authority
In the Linux kernel, the following vulnerability has been resolved: sched/fair: Fix potential memory corruption in child_cfs_rq_on_list child_cfs_rq_on_list attempts to convert a 'prev' pointer to a cfs_rq. This 'prev' pointer can originate from struct rq's leaf_cfs_rq_list, making the conversion invalid and potentially leading to memory corruption. Depending on the relative positions of leaf_cfs_rq_list and the task group (tg) pointer within the struct, this can cause a memory fault or access garbage data. The issue arises in list_add_leaf_cfs_rq, where both cfs_rq->leaf_cfs_rq_list and rq->leaf_cfs_rq_list are added to the same leaf list. Also, rq->tmp_alone_branch can be set to rq->leaf_cfs_rq_list. This adds a check `if (prev == &rq->leaf_cfs_rq_list)` after the main conditional in child_cfs_rq_on_list. This ensures that the container_of operation will convert a correct cfs_rq struct. This check is sufficient because only cfs_rqs on the same CPU are added to the list, so verifying the 'prev' pointer against the current rq's list head is enough. Fixes a potential memory corruption issue that due to current struct layout might not be manifesting as a crash but could lead to unpredictable behavior when the layout changes.
Published by kernel.org, the CVE Numbering Authority that assigned CVE-2025-21919, in its CVE record at CVE.org; reused under the CVE Program's Terms of Use (its licence and MITRE's copyright notice are in our Terms of Service).