CVE-2026-93798

btrfs: fix reloc root cleanup in merge_reloc_roots()

CVSS 3.1 7.8 HIGHCheck source for fixed versionsKEV status unknown

Original advisory

Historical advisory recorded 23 Oct 2026 15:48:27 UTC. Read the latest advisory.

cve-program · CVE-2026-93798

Published

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix reloc root cleanup in merge_reloc_roots() If the root we got has zero root refs in its root item, we are resetting the root's ->reloc_root without using barriers like we do everywhere else. Sashiko complained about this while reviewing another patch, and it's correct (see the Link tag below). Also, we should not clear BTRFS_ROOT_DEAD_RELOC_TREE from the root unless the root points to the reloc root we have. Fix this by using clear_reloc_root(), which issues the memory barrier after setting the root's ->reloc_root to NULL and before clearing the bit BTRFS_ROOT_DEAD_RELOC_TREE from the root.

Read the publisher's advisory

Affected versions, risk and source history

cve-program · CVE-2026-93798

Published

Linux

Vendor product

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "fs/btrfs/relocation.c"
                    ],
                    "versions": [
                        {
                            "version": "1dae7e0e58b484eaa43d530f211098fdeeb0f404",
                            "lessThan": "29531470b1bf1e8bd2df4941fe913106edbca615",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "1dae7e0e58b484eaa43d530f211098fdeeb0f404",
                            "lessThan": "415f8665a969d3c906e4fd7c90fcbb4b357886f6",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "1dae7e0e58b484eaa43d530f211098fdeeb0f404",
                            "lessThan": "ee695a968aa73b1e67ccbf2133dc0e54381d32b2",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "1dae7e0e58b484eaa43d530f211098fdeeb0f404",
                            "lessThan": "0bc25f0a2d1b3e0a691431c4d7aef36afcd527c5",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "1dae7e0e58b484eaa43d530f211098fdeeb0f404",
                            "lessThan": "ab48583aa9948205ff9a6470e23dbff74c565e24",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "1dae7e0e58b484eaa43d530f211098fdeeb0f404",
                            "lessThan": "63d6b1f04cd91c825329712aa526215ffa5d11ca",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "1dae7e0e58b484eaa43d530f211098fdeeb0f404",
                            "lessThan": "b78fe9563e2d5ae47805f1e5dc722c91fd30e1f8",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "ee08663380ffd5a45a1c87580fbc305e8413c235",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "33823378ff2b510fd7b566f25bb18438aeb9b23b",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "5.4.54",
                            "lessThan": "5.5",
                            "status": "affected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.7.11",
                            "lessThan": "5.8",
                            "status": "affected",
                            "versionType": "semver"
                        }
                    ]
                }

Linux

Vendor product

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "fs/btrfs/relocation.c"
                    ],
                    "versions": [
                        {
                            "version": "5.8",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "5.8",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.10.271",
                            "lessThanOrEqual": "5.10.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.15.222",
                            "lessThanOrEqual": "5.15.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.1.189",
                            "lessThanOrEqual": "6.1.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.6.158",
                            "lessThanOrEqual": "6.6.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.111",
                            "lessThanOrEqual": "6.12.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.53",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2",
                            "lessThanOrEqual": "*",
                            "status": "unaffected",
                            "versionType": "original_commit_for_fix"
                        }
                    ]
                }

Original source record · Cite this exact observation · Complete original publisher JSON