# CVE-2025-39878: linux: In the Linux kernel, the following vulnerability has been resolved:  ceph: fix crash after fscrypt_encrypt_pagecache_...

CVE-2025-39878 is fixed in linux on 1 platform by DEBIAN-CVE-2025-39878 (version 6.16.8-1), released September 23, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2025-39878
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0019
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 23, 2025

## Description

In the Linux kernel, the following vulnerability has been resolved:  ceph: fix crash after fscrypt_encrypt_pagecache_blocks() error  The function move_dirty_folio_in_page_array() was created by commit ce80b76dd327 ("ceph: introduce ceph_process_folio_batch() method") by moving code from ceph_writepages_start() to this function.  This new function is supposed to return an error code which is checked by the caller (now ceph_process_folio_batch()), and on error, the caller invokes redirty_page_for_writepage() and then breaks from the loop.  However, the refactoring commit has gone wrong, and it by accident, it always returns 0 (= success) because it first NULLs the pointer and then returns PTR_ERR(NULL) which is always 0.  This means errors are silently ignored, leaving NULL entries in the page array, which may later crash the kernel.  The simple solution is to call PTR_ERR() before clearing the pointer.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 6.16.8-1 | [DEBIAN-CVE-2025-39878](https://patchblox.com/security/data/fix/linux/debian-cve-2025-39878.md) | Sep 23, 2025 |

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