Vulnerability · Published Jul 19, 2026 · Assigned by Linux

CVE-2026-63952memfd: deny writeable mappings when implying SEAL_WRITE

High 8.4

In plain English

A high-severity race condition in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.4High
Exploit odds (30 days)0.1%top 97.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: memfd: deny writeable mappings when implying SEAL_WRITE When SEAL_EXEC is added, SEAL_WRITE is implied to make W^X. But the implied seal is set after the check that makes sure the memfd can not have any writable mappings. This means one can use SEAL_EXEC to apply SEAL_WRITE while having writeable mappings. This breaks the contract that SEAL_WRITE provides and can be used by an attacker to pass a memfd that appears to be write sealed but can still be modified arbitrarily. Fix this by adding the implied seals before the call for mapping_deny_writable() is done.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:10kernel6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-64k6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-64k5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-64k-core6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-64k-core5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-64k-debug6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-64k-debug5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-64k-debug-core6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-64k-debug-core5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-64k-debug-devel6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-64k-debug-devel5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-64k-debug-devel-matched6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-64k-debug-devel-matched5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-64k-debug-modules6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-64k-debug-modules5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-64k-debug-modules-core6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-64k-debug-modules-core5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-64k-debug-modules-extra6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-64k-debug-modules-extra5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-64k-devel6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-64k-devel5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-64k-devel-matched6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-64k-devel-matched5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-64k-modules6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-64k-modules5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-64k-modules-core6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-64k-modules-core5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-64k-modules-extra6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-64k-modules-extra5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-abi-stablelists6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-abi-stablelists5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-core6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-core5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-cross-headers6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-cross-headers5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-debug6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-debug5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-debug-core6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-debug-core5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-debug-devel6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-debug-devel5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-debug-devel-matched6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-debug-devel-matched5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-debug-modules6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-debug-modules5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-debug-modules-core6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-debug-modules-core5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-debug-modules-extra6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-debug-modules-extra5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-debug-uki-virt6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-debug-uki-virt5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-devel6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-devel5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-devel-matched6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-devel-matched5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-doc6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-doc5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-headers6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-headers5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-modules6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-modules5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-modules-core6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-modules-core5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-modules-extra6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-modules-extra5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-modules-extra-matched6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:10kernel-rt6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-64k6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-64k5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-64k-core6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-64k-core5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-64k-debug6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-64k-debug5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-64k-debug-core6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-64k-debug-core5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-64k-debug-devel6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-64k-debug-devel5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-64k-debug-modules6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-64k-debug-modules5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-64k-debug-modules-core6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-64k-debug-modules-core5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-64k-debug-modules-extra6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-64k-debug-modules-extra5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-64k-devel6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-64k-devel5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-64k-modules6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-64k-modules5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-64k-modules-core6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-64k-modules-core5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-64k-modules-extra6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-64k-modules-extra5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-core6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-core5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-debug6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-debug5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-debug-core6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-debug-core5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-debug-devel6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-debug-devel5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-debug-modules6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-debug-modules5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-debug-modules-core6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-debug-modules-core5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-debug-modules-extra6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-debug-modules-extra5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-devel6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-devel5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-modules6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-modules5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-modules-core6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-modules-core5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-rt-modules-extra6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-rt-modules-extra5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-tools6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-tools5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-tools-libs6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-tools-libs5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-tools-libs-devel6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-tools-libs-devel5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-uki-virt6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-uki-virt5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-uki-virt-addons6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-uki-virt-addons5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-zfcpdump6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-zfcpdump5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-zfcpdump-core6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-zfcpdump-core5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-zfcpdump-devel6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-zfcpdump-devel5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-zfcpdump-devel-matched6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-zfcpdump-devel-matched5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-zfcpdump-modules6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-zfcpdump-modules5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-zfcpdump-modules-core6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-zfcpdump-modules-core5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10kernel-zfcpdump-modules-extra6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9kernel-zfcpdump-modules-extra5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10libperf6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9libperf5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10perf6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9perf5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10python3-perf6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9python3-perf5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10rtla6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9rtla5.14.0-687.41.1.el9_8ALSA-2026:57252
AlmaLinux:10rv6.12.0-211.49.1.el10_2ALSA-2026:57251
AlmaLinux:9rv5.14.0-687.41.1.el9_8ALSA-2026:57252
Debian:13linux6.12.94-1DEBIAN-CVE-2026-63952
Debian:14linux7.0.12-1DEBIAN-CVE-2026-63952
Rocky Linux:10kernel0:6.12.0-211.49.1.el10_2RLSA-2026:57251
Rocky Linux:9kernel0:5.14.0-687.41.1.el9_8RLSA-2026:57252
Ubuntu:24.04:LTSlinux6.8.0-146.146UBUNTU-CVE-2026-63952
Ubuntu:26.04:LTSlinux7.0.0-28.28UBUNTU-CVE-2026-63952
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-aws6.8.0-1066.69UBUNTU-CVE-2026-63952
Ubuntu:26.04:LTSlinux-aws7.0.0-1009.9UBUNTU-CVE-2026-63952
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-63952
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-63952
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-63952
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1066.69~22.04.1UBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-azure6.8.0-1070.78UBUNTU-CVE-2026-63952
Ubuntu:26.04:LTSlinux-azure7.0.0-1010.10UBUNTU-CVE-2026-63952
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-63952
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-63952
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-63952
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1070.78~22.04.1UBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-azure-7.07.0.0-1014.14~24.04.1UBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1068.75UBUNTU-CVE-2026-63952
Ubuntu:26.04:LTSlinux-azure-fde7.0.0-1009.9UBUNTU-CVE-2026-63952
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-azure-fde-6.17no fix listedUBUNTU-CVE-2026-63952
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-63952
Ubuntu:22.04:LTSlinux-azure-fde-6.86.8.0-1068.75~22.04.1UBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-azure-fde-7.07.0.0-1013.13~24.04.1UBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-gcp6.8.0-1070.78UBUNTU-CVE-2026-63952
Ubuntu:26.04:LTSlinux-gcp7.0.0-1008.8UBUNTU-CVE-2026-63952
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-63952
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-63952
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-63952
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1070.78~22.04.1UBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-gcp-7.07.0.0-1011.11~24.04.1UBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-gke6.8.0-1065.73UBUNTU-CVE-2026-63952
Ubuntu:26.04:LTSlinux-gke7.0.0-1003.4UBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1051.55UBUNTU-CVE-2026-63952
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-63952
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-63952

Affected products (as reported)

VendorProductVersions
Linux Linux c4f75bc8bd6b3d62665e1f5400c419540edb5601 – before b3f4f82d1315f1439059a83d1c22c51a5b43d99ec4f75bc8bd6b3d62665e1f5400c419540edb5601 – before 3be2a24f7f72ad7321ed6ad1715b956a4527bcf4c4f75bc8bd6b3d62665e1f5400c419540edb5601 – before 0995d1f79aed8ccbf62056189dd53fd19726ea08c4f75bc8bd6b3d62665e1f5400c419540edb5601 – before 555702282d4536a865dfffb1cd4f6028f196e7e8c4f75bc8bd6b3d62665e1f5400c419540edb5601 – before 3b041514cb6eae45869b020f743c14d983363222
Linux Linux 6.3

Weakness: CWE-362 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N

References