What’s Vulnerable › Vulnerabilities

CVE-2026-98831: of/overlay: don't leak fragment references when changeset init fails

• Severity: unknown
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-18 · updated 2026-10-30

Description

In the Linux kernel, the following vulnerability has been resolved: of/overlay: don't leak fragment references when changeset init fails init_overlay_changeset() stores the number of initialized fragments in ovcs->count only on full success. When find_target() or the __symbols__ lookup fails partway through, the target and overlay references taken for the fragments initialized so far are never dropped: free_overlay_changeset() bounds its cleanup loop by ovcs->count, which is still 0. Store the running count on the error path so free_overlay_changeset() puts whatever was set up. The store is guarded by ovcs->fragments because on the allocation-failure path cnt still holds the counting pass total while there is no fragments array; everywhere else cnt only counts fully-initialized fragments.

Affected products

• Linux: 4.15 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux 7.3. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/1d62f0f2bc7edb12ed09f71203df0e47fa4efca4
• https://git.kernel.org/stable/c/3a23fb158ba517b77a2e5258263bdfdaa480f758
• https://git.kernel.org/stable/c/64517aeaa3d8b158e4d01321a095be48cb551251
• https://git.kernel.org/stable/c/702b5db6e7b3865be70675d57d6fd7dde80d02b6
• https://git.kernel.org/stable/c/7a46f1917b320cc8762183b802301da02a191b6a
• https://git.kernel.org/stable/c/894573e2fdaeb1b15030b7eebc22615edf28a6cd
• https://git.kernel.org/stable/c/bbe3dc64b28a14bd9ecb514bbf5115ac8472ed80
• https://git.kernel.org/stable/c/c654f283d7db20648a5bbf979209f78d4fa9be3f

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