# CVE-2026-80719: linux: In the Linux kernel, the following vulnerability has been resolved:  mm: mglru: fix stale batch updates after memcg r...

CVE-2026-80719 is fixed in linux on 1 platform by DEBIAN-CVE-2026-80719 (version 7.1.8-1), released August 29, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-80719
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0020
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 28, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  mm: mglru: fix stale batch updates after memcg reparenting  The mglru page table walker batches per-generation size deltas in walk->nr_pages while walking page tables without holding the lruvec lock.  The reset_batch_size() later folds those deltas into walk->lruvec under the lruvec lock.  The page table walker can run concurrently with the memcg reparenting path as follows:  CPU0                           CPU1 ====                           ====  walk_mm --> walk_page_range     --> update_batch_size         --> walk->nr_pages += delta                                mem_cgroup_css_offline                               --> memcg_reparent_objcgs                                   --> lock lruvec                                       lru_gen_reparent_memcg                                       --> reparent child folios to parent                                       unlock lruvec      lock lruvec     reset_batch_size     --> child lrugen->nr_pages += delta  This will trigger the following warning in lru_gen_exit_memcg():  	VM_WARN_ON_ONCE(memchr_inv(lruvec->lrugen.nr_pages, 0, 				   sizeof(lruvec->lrugen.nr_pages)));  And the user-visible impact of underestimated nr_pages in MGLRU was premature OOMs because MGLRU does not try to reclaim memory when nr_pages reaches zero, but there are still more pages.  To fix it, make reset_batch_size() check CSS_DYING under RCU before flushing the pending batch.  A non-dying memcg keeps the original lruvec stable against RCU-delayed offlining; a dying memcg redirects the deltas to the first non-dying ancestor.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.1.8-1 | [DEBIAN-CVE-2026-80719](https://patchblox.com/security/data/fix/linux/debian-cve-2026-80719.md) | Aug 29, 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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