# CVE-2025-21721: linux: In the Linux kernel, the following vulnerability has been resolved: nilfs2: handle errors that nilfs_prepare_chunk()... CVE-2025-21721 is fixed in 36 products on 1 platform, first by DEBIAN-CVE-2025-21721, released February 27, 2025. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2025-21721 - Priority: Routine - CVSS: 5.5 (medium) - EPSS: 0.0023 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Feb 27, 2025 ## Description In the Linux kernel, the following vulnerability has been resolved: nilfs2: handle errors that nilfs_prepare_chunk() may return Patch series "nilfs2: fix issues with rename operations". This series fixes BUG_ON check failures reported by syzbot around rename operations, and a minor behavioral issue where the mtime of a child directory changes when it is renamed instead of moved. This patch (of 2): The directory manipulation routines nilfs_set_link() and nilfs_delete_entry() rewrite the directory entry in the folio/page previously read by nilfs_find_entry(), so error handling is omitted on the assumption that nilfs_prepare_chunk(), which prepares the buffer for rewriting, will always succeed for these. And if an error is returned, it triggers the legacy BUG_ON() checks in each routine. This assumption is wrong, as proven by syzbot: the buffer layer called by nilfs_prepare_chunk() may call nilfs_get_block() if necessary, which may fail due to metadata corruption or other reasons. This has been there all along, but improved sanity checks and error handling may have made it more reproducible in fuzzing tests. Fix this issue by adding missing error paths in nilfs_set_link(), nilfs_delete_entry(), and their caller nilfs_rename(). ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | kernel-uek ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-core ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-core ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-core ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-core ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-devel ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-devel ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-core ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-core ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-deprecated ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-deprecated ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-desktop ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-desktop ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-extra ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-extra ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-extra-netfilter ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-extra-netfilter ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-usb ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-usb ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-wireless ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-wireless ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-devel ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-devel ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-doc ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-doc ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-core ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-core ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-deprecated ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-deprecated ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-desktop ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-desktop ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-extra ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-extra ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-extra-netfilter ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-extra-netfilter ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-usb ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-usb ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-wireless ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-wireless ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-tools ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-tools ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-core ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-core ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-devel ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-devel ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-core ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-core ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-deprecated ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-deprecated ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-desktop ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-desktop ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-extra ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-extra ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-extra-netfilter ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-extra-netfilter ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-usb ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-usb ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-wireless ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-wireless ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | linux Debian 12.15 (bookworm) | 6.1.133-1 | [DEBIAN-CVE-2025-21721](https://patchblox.com/security/data/fix/linux/debian-cve-2025-21721.md) | Feb 27, 2025 | | Linux | linux Debian 13.5 (trixie) | 6.12.13-1 | [DEBIAN-CVE-2025-21721](https://patchblox.com/security/data/fix/linux/debian-cve-2025-21721.md) | Feb 27, 2025 | | Linux | linux Debian 14 | 6.12.13-1 | [DEBIAN-CVE-2025-21721](https://patchblox.com/security/data/fix/linux/debian-cve-2025-21721.md) | Feb 27, 2025 | --- Data as of 2026-11-09T13:31:49Z UTC. 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