In the Linux kernel, the following vulnerability has been resolved:
zram: fix NULL pointer in comp_algorithm_show()
LTP reported a NULL pointer dereference as followed:
CPU: 7 UID: 0 PID: 5995 Comm: cat Kdump: loaded Not tainted 6.12.0-rc6+ #3 Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 pstate: 40400005 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __pi_strcmp+0x24/0x140 lr : zcomp_available_show+0x60/0x100 [zram] sp : ffff800088b93b90 x29: ffff800088b93b90 x28: 0000000000000001 x27: 0000000000400cc0 x26: 0000000000000ffe x25: ffff80007b3e2388 x24: 0000000000000000 x23: ffff80007b3e2390 x22: ffff0004041a9000 x21: ffff80007b3e2900 x20: 0000000000000000 x19: 0000000000000000 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000000 x10: ffff80007b3e2900 x9 : ffff80007b3cb280 x8 : 0101010101010101 x7 : 0000000000000000 x6 : 0000000000000000 x5 : 0000000000000040 x4 : 0000000000000000 x3 : 00656c722d6f7a6c x2 : 0000000000000000 x1 : ffff80007b3e2900 x0 : 0000000000000000 Call trace: __pi_strcmp+0x24/0x140 comp_algorithm_show+0x40/0x70 [zram] dev_attr_show+0x28/0x80 sysfs_kf_seq_show+0x90/0x140 kernfs_seq_show+0x34/0x48 seq_read_iter+0x1d4/0x4e8 kernfs_fop_read_iter+0x40/0x58 new_sync_read+0x9c/0x168 vfs_read+0x1a8/0x1f8 ksys_read+0x74/0x108 __arm64_sys_read+0x24/0x38 invoke_syscall+0x50/0x120 el0_svc_common.constprop.0+0xc8/0xf0 do_el0_svc+0x24/0x38 el0_svc+0x38/0x138 el0t_64_sync_handler+0xc0/0xc8 el0t_64_sync+0x188/0x190
The zram->comp_algs[ZRAM_PRIMARY_COMP] can be NULL in zram_add() if comp_algorithm_set() has not been called. User can access the zram device by sysfs after device_add_disk(), so there is a time window to trigger the NULL pointer dereference. Move it ahead device_add_disk() to make sure when user can access the zram device, it is ready. comp_algorithm_set() is protected by zram->init_lock in other places and no such problem.
CVSS Details
- CVSS 3.1 Base Score: 5.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Debian | — | Upgrade linux | Jul 27, 2026 | Jul 27, 2026 |
| Oracle_linux | — | Upgrade kernel | Dec 3, 2025 | Dec 27, 2024 |
| Redhat_linux | — | Upgrade kernelNo solution existsUpgrade kernel-rt | May 15, 2025 | Dec 27, 2024 |
| Rocky_linux | — | Upgrade kernel-tools-libsUpgrade kernel-rtUpgrade kernel-zfcpdump-coreUpgrade kernel-develUpgrade kernel-rt-debugUpgrade kernel-tools-libs-develUpgrade kernel-zfcpdump-devel-matchedUpgrade kernel-debuginfo-common-s390xUpgrade kernel-uki-virt-addonsUpgrade kernel-rt-debug-coreUpgrade python3-perfUpgrade kernel-rt-debug-modules-coreUpgrade kernel-uki-virtUpgrade kernel-rt-debug-modules-extraUpgrade kernel-rt-develUpgrade kernel-zfcpdumpUpgrade kernel-toolsUpgrade libperf-debuginfoUpgrade rvUpgrade kernel-rt-debug-debuginfoUpgrade kernel-rt-debug-modulesUpgrade kernel-rt-debuginfoUpgrade kernel-tools-debuginfoUpgrade perf-debuginfoUpgrade kernel-rt-modulesUpgrade python3-perf-debuginfoUpgrade perfUpgrade kernel-debug-uki-virtUpgrade kernel-debuginfo-common-x86_64Upgrade kernel-rt-modules-extraUpgrade kernel-rt-modules-coreUpgrade kernel-coreUpgrade kernel-devel-matchedUpgrade kernel-modules-coreUpgrade kernel-debug-coreUpgrade kernel-modules-extraUpgrade kernel-modules-extra-matchedUpgrade kernel-zfcpdump-modulesUpgrade rtlaUpgrade kernel-zfcpdump-modules-extraUpgrade kernel-zfcpdump-modules-coreUpgrade kernel-zfcpdump-debuginfoUpgrade kernel-modulesUpgrade kernel-debug-debuginfoUpgrade kernel-zfcpdump-develUpgrade kernelUpgrade kernel-debug-develUpgrade kernel-debuginfoUpgrade kernel-debug-modulesUpgrade libperfUpgrade kernel-debug-devel-matchedUpgrade kernel-rt-coreUpgrade kernel-debugUpgrade kernel-debug-modules-extraUpgrade kernel-debug-modules-coreUpgrade kernel-rt-debug-devel | Feb 5, 2026 | Nov 27, 2025 |
| Ubuntu | — | Upgrade linux-image-ibm-classicUpgrade linux-image-gcp-64k-lts-24.04Upgrade linux-image-generic-64kUpgrade linux-image-6.11.0-28-genericUpgrade linux-image-6.8.0-1026-nvidiaUpgrade linux-image-virtualUpgrade linux-image-6.8.0-58-generic-64kUpgrade linux-image-6.8.0-1024-oracle-64kUpgrade linux-image-6.8.0-58-genericUpgrade linux-image-nvidia-lowlatency-64kUpgrade linux-image-azure-lts-24.04Upgrade linux-image-virtual-hwe-24.04Upgrade linux-image-6.8.0-1026-nvidia-lowlatencyUpgrade linux-image-6.11.0-1018-azureUpgrade linux-image-6.11.0-1015-awsUpgrade linux-image-6.8.0-1027-awsUpgrade linux-image-lowlatency-hwe-24.04Upgrade linux-image-6.8.0-1026-nvidia-lowlatency-64kUpgrade linux-image-genericUpgrade linux-image-gkeopUpgrade linux-image-lowlatency-hwe-22.04Upgrade linux-image-6.8.0-1028-gcpUpgrade linux-image-6.8.0-58-lowlatencyUpgrade linux-image-azure-fdeUpgrade linux-image-azure-nvidiaUpgrade linux-image-nvidia-64k-hwe-22.04Upgrade linux-image-lowlatencyUpgrade linux-image-generic-lpaeUpgrade linux-image-oem-24.04bUpgrade linux-image-lowlatency-64k-hwe-24.04Upgrade linux-image-oracle-lts-24.04Upgrade linux-image-nvidiaUpgrade linux-image-6.11.0-1017-oracle-64kUpgrade linux-image-6.8.0-2023-raspi-realtimeUpgrade linux-image-oem-24.04Upgrade linux-image-oem-22.04Upgrade linux-image-6.8.0-1028-raspiUpgrade linux-image-gkeop-6.8Upgrade linux-image-oem-22.04aUpgrade linux-image-nvidia-64k-6.8Upgrade linux-image-azure-fde-edgeUpgrade linux-image-azure-6.11Upgrade linux-image-ibmUpgrade linux-image-6.11.0-1011-realtimeUpgrade linux-image-oracleUpgrade linux-image-6.8.1-1020-realtimeUpgrade linux-image-lowlatency-64kUpgrade linux-image-6.8.0-1027-azureUpgrade linux-image-raspiUpgrade linux-image-generic-hwe-22.04Upgrade linux-image-lowlatency-64k-6.11Upgrade linux-image-kvmUpgrade linux-image-gcpUpgrade linux-image-6.8.0-1023-gkeUpgrade linux-image-gkeUpgrade linux-image-virtual-hwe-22.04Upgrade linux-image-azureUpgrade linux-image-6.8.0-1014-azure-nvidiaUpgrade linux-image-awsUpgrade linux-image-nvidia-6.8Upgrade linux-image-6.11.0-1014-raspiUpgrade linux-image-azure-fde-6.11Upgrade linux-image-6.11.0-1015-lowlatency-64kUpgrade linux-image-ibm-lts-24.04Upgrade linux-image-6.8.0-58-lowlatency-64kUpgrade linux-image-6.11.0-1015-lowlatencyUpgrade linux-image-realtimeUpgrade linux-image-oem-24.04aUpgrade linux-image-6.8.0-1028-gcp-64kUpgrade linux-image-raspi-realtimeUpgrade linux-image-generic-hwe-24.04Upgrade linux-image-6.11.0-1016-gcp-64kUpgrade linux-image-6.8.0-1026-nvidia-64kUpgrade linux-image-lowlatency-64k-hwe-22.04Upgrade linux-image-gcp-lts-24.04Upgrade linux-image-oem-22.04bUpgrade linux-image-gcp-64kUpgrade linux-image-generic-64k-hwe-24.04Upgrade linux-image-azure-fde-lts-24.04Upgrade linux-image-6.8.0-1010-gkeopUpgrade linux-image-nvidia-64kUpgrade linux-image-oem-22.04dUpgrade linux-image-realtime-hwe-24.04Upgrade linux-image-6.11.0-28-generic-64kUpgrade linux-image-oracle-64kUpgrade linux-image-oem-22.04cUpgrade linux-image-6.8.0-1026-oemUpgrade linux-image-6.11.0-1024-oemUpgrade linux-image-6.8.0-1024-ibmUpgrade linux-image-6.11.0-1018-azure-fdeUpgrade linux-image-6.11.0-1016-gcpUpgrade linux-image-nvidia-lowlatencyUpgrade linux-image-lowlatency-6.11Upgrade linux-image-generic-64k-hwe-22.04Upgrade linux-image-aws-lts-24.04Upgrade linux-image-6.8.0-1027-azure-fdeUpgrade linux-image-6.8.0-1024-oracleUpgrade linux-image-nvidia-hwe-22.04Upgrade linux-image-6.11.0-1017-oracleUpgrade linux-image-oracle-64k-lts-24.04 | Apr 24, 2025 | Dec 27, 2024 |
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