# CVE-2026-23147: linux: In the Linux kernel, the following vulnerability has been resolved:  btrfs: zlib: fix the folio leak on S390 hardware...

CVE-2026-23147 is fixed in linux on 1 platform by DEBIAN-CVE-2026-23147 (version 6.18.9-1), released February 14, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-23147
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0013
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Feb 14, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  btrfs: zlib: fix the folio leak on S390 hardware acceleration  [BUG] After commit aa60fe12b4f4 ("btrfs: zlib: refactor S390x HW acceleration buffer preparation"), we no longer release the folio of the page cache of folio returned by btrfs_compress_filemap_get_folio() for S390 hardware acceleration path.  [CAUSE] Before that commit, we call kumap_local() and folio_put() after handling each folio.  Although the timing is not ideal (it release previous folio at the beginning of the loop, and rely on some extra cleanup out of the loop), it at least handles the folio release correctly.  Meanwhile the refactored code is easier to read, it lacks the call to release the filemap folio.  [FIX] Add the missing folio_put() for copy_data_into_buffer().

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 6.18.9-1 | [DEBIAN-CVE-2026-23147](https://patchblox.com/security/data/fix/linux/debian-cve-2026-23147.md) | Feb 14, 2026 |

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Data as of 2026-11-09T01:18:40Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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