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linux — security advisory

Type: advisorySources: OSVAdvisory ID: DEBIAN-CVE-2021-47646

In the Linux kernel, the following vulnerability has been resolved: Revert "Revert "block, bfq: honor already-setup queue merges"" A crash [1] happened to be triggered in conjunction with commit 2d52c58b9c9b ("block, bfq: honor already-setup queue merges"). The latter was then reverted by commit ebc69e897e17 ("Revert "block, bfq: honor already-setup queue merges""). Yet, the reverted commit was not the one introducing the bug. In fact, it actually triggered a UAF introduced by a different commit, and now fixed by commit d29bd41428cf ("block, bfq: reset last_bfqq_created on group change"). So, there is no point in keeping commit 2d52c58b9c9b ("block, bfq: honor already-setup queue merges") out. This commit restores it. [1] https://bugzilla.kernel.org/show_bug.cgi?id=214503

Products
linux
Affected versions
Not specified
Fixed versions
5.17.3-1
CVEs
CVE-2021-47646
Confirmed fixed CVEs
Not specified
Updated in this feed
1 Nov 2026, 01:16 UTC · Revision 1

Source evidence

DEBIAN-CVE-2021-47646

core-osv · Original source

Published 26 Feb 2025, 06:37 UTC

In the Linux kernel, the following vulnerability has been resolved: Revert "Revert "block, bfq: honor already-setup queue merges"" A crash [1] happened to be triggered in conjunction with commit 2d52c58b9c9b ("block, bfq: honor already-setup queue merges"). The latter was then reverted by commit ebc69e897e17 ("Revert "block, bfq: honor already-setup queue merges""). Yet, the reverted commit was not the one introducing the bug. In fact, it actually triggered a UAF introduced by a different commit, and now fixed by commit d29bd41428cf ("block, bfq: reset last_bfqq_created on group change"). So, there is no point in keeping commit 2d52c58b9c9b ("block, bfq: honor already-setup queue merges") out. This commit restores it. [1] https://bugzilla.kernel.org/show_bug.cgi?id=214503

osv:DEBIAN-CVE-2021-47646

linux

Fixed versions: 5.17.3-1

linux

Fixed versions: 5.17.3-1

linux

Fixed versions: 5.17.3-1

Complete source record
{
  "id": "e600b3af026bde39c194db15dfd49a1f78956bc1e6b31b7249e78878800dfb0d",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2021-47646",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2021-47646",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: Revert \"Revert \"block, bfq: honor already-setup queue merges\"\" A crash [1] happened to be triggered in conjunction with commit 2d52c58b9c9b (\"block, bfq: honor already-setup queue merges\"). The latter was then reverted by commit ebc69e897e17 (\"Revert \"block, bfq: honor already-setup queue merges\"\"). Yet, the reverted commit was not the one introducing the bug. In fact, it actually triggered a UAF introduced by a different commit, and now fixed by commit d29bd41428cf (\"block, bfq: reset last_bfqq_created on group change\"). So, there is no point in keeping commit 2d52c58b9c9b (\"block, bfq: honor already-setup queue merges\") out. This commit restores it. [1] https://bugzilla.kernel.org/show_bug.cgi?id=214503",
    "evidence": "osv:DEBIAN-CVE-2021-47646",
    "products": [
      {
        "name": {
          "value": "linux",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.17.3-1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "linux",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.17.3-1",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "linux",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.17.3-1",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "DEBIAN-CVE-2021-47646",
      "aliases": [
        "DEBIAN-CVE-2021-47646"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "5.17.3-1"
                }
              ]
            }
          ],
          "package": {
            "name": "linux",
            "purl": "pkg:deb/debian/linux?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-47646.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "5.17.3-1"
                }
              ]
            }
          ],
          "package": {
            "name": "linux",
            "purl": "pkg:deb/debian/linux?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-47646.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "5.17.3-1"
                }
              ]
            }
          ],
          "package": {
            "name": "linux",
            "purl": "pkg:deb/debian/linux?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-47646.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-23T18:04:21.082699174Z",
      "provider": "osv",
      "upstream": [
        "CVE-2021-47646"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2021-47646"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2021-47646",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 423536,
  "published_at": "2025-02-26T06:37:06.39+00:00"
}