CVE-2026-93798
HIGH 7.8In 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.
Severe if exploited (CVSS 7.8), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
0.1%chance of exploitation in 30 days · 3rd percentile
Impact if exploited
7.8CVSS 3.1 · HIGH
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityHigh
What an attacker needs
- ⚠Access: Requires local access to the host
- ⚠Privileges: Requires a low-privilege account
- ✓User interaction: No user interaction needed
- ✓Complexity: No special conditions — reliably repeatable
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept
No public PoC is currently catalogued.
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Data snapshot:
Weakness (CWE)
Not classified.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
References and research data (JSON)
Vendor product assessments
Showing 32 of 277 vendor product statements; 245 omitted. Read the full vendor advisory.
kernel as a component of Red Hat Enterprise Linux 10 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel
- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
- none available: Fix deferred
kernel-64k-debug-devel-matched as a component of Red Hat Enterprise Linux 10 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-64k-debug-devel-matched
- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
- none available: Fix deferred
kernel-64k-modules as a component of Red Hat Enterprise Linux 10 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-64k-modules
- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
- none available: Fix deferred
kernel-debug-core as a component of Red Hat Enterprise Linux 10 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-debug-core
- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
- none available: Fix deferred
kernel-debug-uki-virt as a component of Red Hat Enterprise Linux 10 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-debug-uki-virt
- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
- none available: Fix deferred
kernel-modules-extra as a component of Red Hat Enterprise Linux 10 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-modules-extra
- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
- none available: Fix deferred
kernel-rt-64k-debug as a component of Red Hat Enterprise Linux 10 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-rt-64k-debug
- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
- none available: Fix deferred
kernel-rt-64k-devel as a component of Red Hat Enterprise Linux 10 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-rt-64k-devel
- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
- none available: Fix deferred
kernel-rt-debug-core as a component of Red Hat Enterprise Linux 10 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-rt-debug-core
- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
- none available: Fix deferred
kernel-rt-devel as a component of Red Hat Enterprise Linux 10 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-rt-devel
- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
- none available: Fix deferred
kernel-tools-libs as a component of Red Hat Enterprise Linux 10 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-tools-libs
- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
- none available: Fix deferred
kernel-zfcpdump-devel as a component of Red Hat Enterprise Linux 10 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-zfcpdump-devel
- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
- none available: Fix deferred
libperf as a component of Red Hat Enterprise Linux 10 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/libperf
- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
- none available: Fix deferred
kernel-abi-whitelists as a component of Red Hat Enterprise Linux 6 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-abi-whitelists
- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
- no fix planned: Out of support scope
kernel-firmware as a component of Red Hat Enterprise Linux 6 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/kernel-firmware
- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
- no fix planned: Out of support scope
python-perf as a component of Red Hat Enterprise Linux 6 · known affected
Vendor assessment for this product only.
pkg:rpm/redhat/python-perf
- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
- no fix planned: Out of support scope
bpftool as a component of Red Hat Enterprise Linux 7 · known not affected
Vendor assessment for this product only.
Reason: vulnerable code not present
pkg:rpm/redhat/bpftool
Red Hat · CVE-2026-93798 · Updated 2026-10-17T21:46:43+00:00kernel-rt-debug as a component of Red Hat Enterprise Linux 7 · known not affected
Vendor assessment for this product only.
Reason: vulnerable code not present
pkg:rpm/redhat/kernel-rt-debug
Red Hat · CVE-2026-93798 · Updated 2026-10-17T21:46:43+00:00kernel.src as a component of Red Hat Enterprise Linux 7 · known not affected
Vendor assessment for this product only.
Reason: vulnerable code not present
pkg:rpm/redhat/kernel?arch=src
Red Hat · CVE-2026-93798 · Updated 2026-10-17T21:46:43+00:00kernel-debug-modules as a component of Red Hat Enterprise Linux 8 · known not affected
Vendor assessment for this product only.
Reason: vulnerable code not present
pkg:rpm/redhat/kernel-debug-modules
Red Hat · CVE-2026-93798 · Updated 2026-10-17T21:46:43+00:00kernel-rt-debug as a component of Red Hat Enterprise Linux 8 · known not affected
Vendor assessment for this product only.
Reason: vulnerable code not present
pkg:rpm/redhat/kernel-rt-debug
Red Hat · CVE-2026-93798 · Updated 2026-10-17T21:46:43+00:00kernel-rt.src as a component of Red Hat Enterprise Linux 8 · known not affected
Vendor assessment for this product only.
Reason: vulnerable code not present
pkg:rpm/redhat/kernel-rt?arch=src
Red Hat · CVE-2026-93798 · Updated 2026-10-17T21:46:43+00:00perf as a component of Red Hat Enterprise Linux 8 · known not affected
Vendor assessment for this product only.
Reason: vulnerable code not present
pkg:rpm/redhat/perf
Red Hat · CVE-2026-93798 · Updated 2026-10-17T21:46:43+00:00kernel-64k-debug-modules-extra as a component of Red Hat Enterprise Linux 9 · known not affected
Vendor assessment for this product only.
Reason: vulnerable code not present
pkg:rpm/redhat/kernel-64k-debug-modules-extra
Red Hat · CVE-2026-93798 · Updated 2026-10-17T21:46:43+00:00kernel-debug as a component of Red Hat Enterprise Linux 9 · known not affected
Vendor assessment for this product only.
Reason: vulnerable code not present
pkg:rpm/redhat/kernel-debug
Red Hat · CVE-2026-93798 · Updated 2026-10-17T21:46:43+00:00kernel-devel-matched as a component of Red Hat Enterprise Linux 9 · known not affected
Vendor assessment for this product only.
Reason: vulnerable code not present
pkg:rpm/redhat/kernel-devel-matched
Red Hat · CVE-2026-93798 · Updated 2026-10-17T21:46:43+00:00kernel-rt-64k-debug as a component of Red Hat Enterprise Linux 9 · known not affected
Vendor assessment for this product only.
Reason: vulnerable code not present
pkg:rpm/redhat/kernel-rt-64k-debug
Red Hat · CVE-2026-93798 · Updated 2026-10-17T21:46:43+00:00kernel-rt-64k-modules as a component of Red Hat Enterprise Linux 9 · known not affected
Vendor assessment for this product only.
Reason: vulnerable code not present
pkg:rpm/redhat/kernel-rt-64k-modules
Red Hat · CVE-2026-93798 · Updated 2026-10-17T21:46:43+00:00kernel-rt-debug-modules-core as a component of Red Hat Enterprise Linux 9 · known not affected
Vendor assessment for this product only.
Reason: vulnerable code not present
pkg:rpm/redhat/kernel-rt-debug-modules-core
Red Hat · CVE-2026-93798 · Updated 2026-10-17T21:46:43+00:00kernel-rt-selftests-internal as a component of Red Hat Enterprise Linux 9 · known not affected
Vendor assessment for this product only.
Reason: vulnerable code not present
pkg:rpm/redhat/kernel-rt-selftests-internal
Red Hat · CVE-2026-93798 · Updated 2026-10-17T21:46:43+00:00kernel-zfcpdump-modules-core as a component of Red Hat Enterprise Linux 9 · known not affected
Vendor assessment for this product only.
Reason: vulnerable code not present
pkg:rpm/redhat/kernel-zfcpdump-modules-core
Red Hat · CVE-2026-93798 · Updated 2026-10-17T21:46:43+00:00openshift/ose-rhel-coreos-9 as a component of Red Hat OpenShift Container Platform 4 · known not affected
Vendor assessment for this product only.
Reason: vulnerable code not present
pkg:oci/ose-rhel-coreos-9?repository_url=registry.redhat.io/openshift/ose-rhel-coreos-9
Red Hat · CVE-2026-93798 · Updated 2026-10-17T21:46:43+00:00
All CVSS metrics
- HIGH 7.8 v3.1 · CNA Primary
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - HIGH 7.8 v3.1 · NVD Secondary
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
References
Advisories
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-93798.json Red Hat · CVE-2026-93798 · Updated 2026-10-17T21:46:43+00:00
- https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-86185 EUVD · EUVD-2026-86185
Technical & other
- https://git.kernel.org/stable/c/29531470b1bf1e8bd2df4941fe913106edbca615CVE record · Linux · Updated 2026-10-03T10:57:32.550Z
NVD · CVE-2026-93798 · Updated 2026-10-03T11:17:49.337 - https://git.kernel.org/stable/c/415f8665a969d3c906e4fd7c90fcbb4b357886f6CVE record · Linux · Updated 2026-10-03T10:57:32.550Z
NVD · CVE-2026-93798 · Updated 2026-10-03T11:17:49.337 - https://git.kernel.org/stable/c/ee695a968aa73b1e67ccbf2133dc0e54381d32b2CVE record · Linux · Updated 2026-10-03T10:57:32.550Z
NVD · CVE-2026-93798 · Updated 2026-10-03T11:17:49.337 - https://git.kernel.org/stable/c/0bc25f0a2d1b3e0a691431c4d7aef36afcd527c5CVE record · Linux · Updated 2026-10-03T10:57:32.550Z
NVD · CVE-2026-93798 · Updated 2026-10-03T11:17:49.337 - https://git.kernel.org/stable/c/ab48583aa9948205ff9a6470e23dbff74c565e24CVE record · Linux · Updated 2026-10-03T10:57:32.550Z
NVD · CVE-2026-93798 · Updated 2026-10-03T11:17:49.337 - https://git.kernel.org/stable/c/63d6b1f04cd91c825329712aa526215ffa5d11caCVE record · Linux · Updated 2026-10-03T10:57:32.550Z
NVD · CVE-2026-93798 · Updated 2026-10-03T11:17:49.337 - https://git.kernel.org/stable/c/b78fe9563e2d5ae47805f1e5dc722c91fd30e1f8CVE record · Linux · Updated 2026-10-03T10:57:32.550Z
NVD · CVE-2026-93798 · Updated 2026-10-03T11:17:49.337 - https://access.redhat.com/security/cve/CVE-2026-93798 Red Hat · CVE-2026-93798 · Updated 2026-10-17T21:46:43+00:00
- https://bugzilla.redhat.com/show_bug.cgi?id=2540560 Red Hat · CVE-2026-93798 · Updated 2026-10-17T21:46:43+00:00
- https://www.cve.org/CVERecord?id=CVE-2026-93798 Red Hat · CVE-2026-93798 · Updated 2026-10-17T21:46:43+00:00
- https://nvd.nist.gov/vuln/detail/CVE-2026-93798 Red Hat · CVE-2026-93798 · Updated 2026-10-17T21:46:43+00:00
- https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-93798.mbox Red Hat · CVE-2026-93798 · Updated 2026-10-17T21:46:43+00:00