{"api_version":"1","generated_at":"2026-07-23T12:47:35+00:00","cve":"CVE-2026-63804","urls":{"html":"https://cve.report/CVE-2026-63804","api":"https://cve.report/api/cve/CVE-2026-63804.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-63804","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-63804"},"summary":{"title":"gfs2: fix use-after-free in gfs2_qd_dealloc","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ngfs2: fix use-after-free in gfs2_qd_dealloc\n\ngfs2_qd_dealloc(), called as an RCU callback from gfs2_qd_dispose(),\naccesses the superblock object sdp through qd->qd_sbd after freeing qd.\nIt does so to decrement sd_quota_count and wake up sd_kill_wait.\n\nHowever, by the time the RCU callback runs, gfs2_put_super() may have\nalready freed sdp via free_sbd().  This can happen when\ngfs2_quota_cleanup() is called during unmount: it disposes of quota\nobjects via call_rcu() and then waits on sd_kill_wait with a 60-second\ntimeout.  If the timeout expires, or if gfs2_gl_hash_clear() triggers\nadditional qd_put() calls that schedule more RCU callbacks after the\nwait completes, gfs2_put_super() will proceed to free the superblock\nwhile RCU callbacks referencing it are still pending.\n\nAdd an rcu_barrier() before free_sbd() in gfs2_put_super() to ensure\nall pending RCU callbacks (including gfs2_qd_dealloc) have completed\nbefore the superblock is freed.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-19 12:16:53","updated_at":"2026-07-19 12:16:53"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/f9c9ec2c319f843b70ecdf939d48b52d189bc081","name":"https://git.kernel.org/stable/c/f9c9ec2c319f843b70ecdf939d48b52d189bc081","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/b85ef03f726b15047a6fa6d11b639bdf6c0ee4f0","name":"https://git.kernel.org/stable/c/b85ef03f726b15047a6fa6d11b639bdf6c0ee4f0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4fe388218826df8607ae41a6305df67db08a9093","name":"https://git.kernel.org/stable/c/4fe388218826df8607ae41a6305df67db08a9093","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/8745d9f7e1682c39f0a1578895ac74205e2a6757","name":"https://git.kernel.org/stable/c/8745d9f7e1682c39f0a1578895ac74205e2a6757","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9d0d5ba20cad661f7f287d4c66d2c19022ce2fd0","name":"https://git.kernel.org/stable/c/9d0d5ba20cad661f7f287d4c66d2c19022ce2fd0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-63804","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63804","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a475c5dd16e57c570113eccba51955b5df8bb052 4fe388218826df8607ae41a6305df67db08a9093 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a475c5dd16e57c570113eccba51955b5df8bb052 8745d9f7e1682c39f0a1578895ac74205e2a6757 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a475c5dd16e57c570113eccba51955b5df8bb052 b85ef03f726b15047a6fa6d11b639bdf6c0ee4f0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a475c5dd16e57c570113eccba51955b5df8bb052 9d0d5ba20cad661f7f287d4c66d2c19022ce2fd0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a475c5dd16e57c570113eccba51955b5df8bb052 f9c9ec2c319f843b70ecdf939d48b52d189bc081 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.6","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.144 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.95 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.38 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.3 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"63804","cve":"CVE-2026-63804","epss":"0.001680000","percentile":"0.063820000","score_date":"2026-07-20","updated_at":"2026-07-21 00:13:14"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["fs/gfs2/super.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"4fe388218826df8607ae41a6305df67db08a9093","status":"affected","version":"a475c5dd16e57c570113eccba51955b5df8bb052","versionType":"git"},{"lessThan":"8745d9f7e1682c39f0a1578895ac74205e2a6757","status":"affected","version":"a475c5dd16e57c570113eccba51955b5df8bb052","versionType":"git"},{"lessThan":"b85ef03f726b15047a6fa6d11b639bdf6c0ee4f0","status":"affected","version":"a475c5dd16e57c570113eccba51955b5df8bb052","versionType":"git"},{"lessThan":"9d0d5ba20cad661f7f287d4c66d2c19022ce2fd0","status":"affected","version":"a475c5dd16e57c570113eccba51955b5df8bb052","versionType":"git"},{"lessThan":"f9c9ec2c319f843b70ecdf939d48b52d189bc081","status":"affected","version":"a475c5dd16e57c570113eccba51955b5df8bb052","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/gfs2/super.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.6"},{"lessThan":"6.6","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.144","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.95","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.38","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.3","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.144","versionStartIncluding":"6.6","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.95","versionStartIncluding":"6.6","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.38","versionStartIncluding":"6.6","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.3","versionStartIncluding":"6.6","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2-rc1","versionStartIncluding":"6.6","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ngfs2: fix use-after-free in gfs2_qd_dealloc\n\ngfs2_qd_dealloc(), called as an RCU callback from gfs2_qd_dispose(),\naccesses the superblock object sdp through qd->qd_sbd after freeing qd.\nIt does so to decrement sd_quota_count and wake up sd_kill_wait.\n\nHowever, by the time the RCU callback runs, gfs2_put_super() may have\nalready freed sdp via free_sbd().  This can happen when\ngfs2_quota_cleanup() is called during unmount: it disposes of quota\nobjects via call_rcu() and then waits on sd_kill_wait with a 60-second\ntimeout.  If the timeout expires, or if gfs2_gl_hash_clear() triggers\nadditional qd_put() calls that schedule more RCU callbacks after the\nwait completes, gfs2_put_super() will proceed to free the superblock\nwhile RCU callbacks referencing it are still pending.\n\nAdd an rcu_barrier() before free_sbd() in gfs2_put_super() to ensure\nall pending RCU callbacks (including gfs2_qd_dealloc) have completed\nbefore the superblock is freed."}],"providerMetadata":{"dateUpdated":"2026-07-19T12:02:09.111Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/4fe388218826df8607ae41a6305df67db08a9093"},{"url":"https://git.kernel.org/stable/c/8745d9f7e1682c39f0a1578895ac74205e2a6757"},{"url":"https://git.kernel.org/stable/c/b85ef03f726b15047a6fa6d11b639bdf6c0ee4f0"},{"url":"https://git.kernel.org/stable/c/9d0d5ba20cad661f7f287d4c66d2c19022ce2fd0"},{"url":"https://git.kernel.org/stable/c/f9c9ec2c319f843b70ecdf939d48b52d189bc081"}],"title":"gfs2: fix use-after-free in gfs2_qd_dealloc","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-63804","datePublished":"2026-07-19T12:02:09.111Z","dateReserved":"2026-07-19T07:54:57.013Z","dateUpdated":"2026-07-19T12:02:09.111Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-19 12:16:53","lastModifiedDate":"2026-07-19 12:16:53","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"63804","Ordinal":"1","Title":"gfs2: fix use-after-free in gfs2_qd_dealloc","CVE":"CVE-2026-63804","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"63804","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\ngfs2: fix use-after-free in gfs2_qd_dealloc\n\ngfs2_qd_dealloc(), called as an RCU callback from gfs2_qd_dispose(),\naccesses the superblock object sdp through qd->qd_sbd after freeing qd.\nIt does so to decrement sd_quota_count and wake up sd_kill_wait.\n\nHowever, by the time the RCU callback runs, gfs2_put_super() may have\nalready freed sdp via free_sbd().  This can happen when\ngfs2_quota_cleanup() is called during unmount: it disposes of quota\nobjects via call_rcu() and then waits on sd_kill_wait with a 60-second\ntimeout.  If the timeout expires, or if gfs2_gl_hash_clear() triggers\nadditional qd_put() calls that schedule more RCU callbacks after the\nwait completes, gfs2_put_super() will proceed to free the superblock\nwhile RCU callbacks referencing it are still pending.\n\nAdd an rcu_barrier() before free_sbd() in gfs2_put_super() to ensure\nall pending RCU callbacks (including gfs2_qd_dealloc) have completed\nbefore the superblock is freed.","Type":"Description","Title":"gfs2: fix use-after-free in gfs2_qd_dealloc"}]}}}