# CVE-2026-98788: futex: Fix private hash use-after-free on resize

CVE-2026-98788 is fixed in linux on 1 platform by DEBIAN-CVE-2026-98788 (version 7.2.10-1), released October 19, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-98788
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0016
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 18, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-98788

## Description

In the Linux kernel, the following vulnerability has been resolved:  futex: Fix private hash use-after-free on resize  poll_state_synchronize_rcu(mm->futex.phash.batches) is used by futex_ref_drop() to check that a grace period has passed since the current hash was published. This relies on batches referencing a grace period which started after the hash pointer was assigned.  __futex_pivot_hash() sets mmph->batches before it replaces mmph->hash:      scoped_guard(rcu) {             mmph->batches = get_state_synchronize_rcu();             rcu_assign_pointer(mmph->hash, new);     }  The scoped_guard(rcu) doesn't stop new grace periods from starting, and if one starts between those two assignments, futex_ref_drop() can move forward while a reader still holds a pointer to the old hash.  Fix things by setting mmph->batches after assigning mmph->hash.  The scoped_guard(rcu) isn't needed, so let's drop that as well.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.2.10-1 | [DEBIAN-CVE-2026-98788](https://patchblox.com/security/data/fix/linux/debian-cve-2026-98788.md) | Oct 19, 2026 |

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Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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