An update for kernel is now available for openEuler-22.03-LTS-SP4 Security Advisory openeuler-security@openeuler.org openEuler security committee openEuler-SA-2026-1831 Final 1.0 1.0 2026-04-03 Initial 2026-04-03 2026-04-03 openEuler SA Tool V1.0 2026-04-03 kernel security update An update for kernel is now available for openEuler-22.03-LTS-SP4 The Linux Kernel, the operating system core itself. Security Fix(es): A vulnerability exists in the RDMA/umad component of the Linux kernel when processing user-space data. The ib_umad_write function calculates data_len based on user-controlled count and MAD header sizes. When a mismatched user MAD header size and RMPP header length are provided, data_len can become negative and be passed to the ib_create_send_mad() function. This can cause subsequent padding calculations to exceed the segment size, ultimately triggering an out-of-bounds memory write (memset) in the alloc_send_rmpp_list() function. An attacker could potentially exploit this vulnerability to cause kernel memory corruption, affecting system stability and confidentiality.(CVE-2026-23243) In the Linux kernel, the following vulnerability has been resolved: x86/efi: defer freeing of boot services memory efi_free_boot_services() frees memory occupied by EFI_BOOT_SERVICES_CODE and EFI_BOOT_SERVICES_DATA using memblock_free_late(). There are two issue with that: memblock_free_late() should be used for memory allocated with memblock_alloc() while the memory reserved with memblock_reserve() should be freed with free_reserved_area(). More acutely, with CONFIG_DEFERRED_STRUCT_PAGE_INIT=y efi_free_boot_services() is called before deferred initialization of the memory map is complete. Benjamin Herrenschmidt reports that this causes a leak of ~140MB of RAM on EC2 t3a.nano instances which only have 512MB or RAM. If the freed memory resides in the areas that memory map for them is still uninitialized, they won't be actually freed because memblock_free_late() calls memblock_free_pages() and the latter skips uninitialized pages. Using free_reserved_area() at this point is also problematic because __free_page() accesses the buddy of the freed page and that again might end up in uninitialized part of the memory map. Delaying the entire efi_free_boot_services() could be problematic because in addition to freeing boot services memory it updates efi.memmap without any synchronization and that's undesirable late in boot when there is concurrency. More robust approach is to only defer freeing of the EFI boot services memory. Split efi_free_boot_services() in two. First efi_unmap_boot_services() collects ranges that should be freed into an array then efi_free_boot_services() later frees them after deferred init is complete.(CVE-2026-23352) In the Linux kernel, a vulnerability has been resolved in Squashfs component: check metadata block offset is within range. Syzkaller reports a "general protection fault in squashfs_copy_data". This is ultimately caused by a corrupted index look-up table, which produces a negative metadata block offset. This is subsequently passed to squashfs_copy_data (via squashfs_read_metadata) where the negative offset causes an out of bounds access. The fix is to check that the offset is within range in squashfs_read_metadata. This will trap this and other cases.(CVE-2026-23388) An update for kernel is now available for openEuler-22.03-LTS-SP4/openEuler-22.03-LTS-SP3. openEuler Security has rated this update as having a security impact of high. A Common Vunlnerability Scoring System(CVSS)base score,which gives a detailed severity rating, is available for each vulnerability from the CVElink(s) in the References section. High kernel https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-1831 https://www.openeuler.org/en/security/cve/detail/?cveId=CVE-2026-23243 https://www.openeuler.org/en/security/cve/detail/?cveId=CVE-2026-23352 https://www.openeuler.org/en/security/cve/detail/?cveId=CVE-2026-23388 https://nvd.nist.gov/vuln/detail/CVE-2026-23243 https://nvd.nist.gov/vuln/detail/CVE-2026-23352 https://nvd.nist.gov/vuln/detail/CVE-2026-23388 openEuler-22.03-LTS-SP4 bpftool-5.10.0-307.0.0.210.oe2203sp4.x86_64.rpm bpftool-debuginfo-5.10.0-307.0.0.210.oe2203sp4.x86_64.rpm kernel-5.10.0-307.0.0.210.oe2203sp4.x86_64.rpm kernel-debuginfo-5.10.0-307.0.0.210.oe2203sp4.x86_64.rpm kernel-debugsource-5.10.0-307.0.0.210.oe2203sp4.x86_64.rpm kernel-devel-5.10.0-307.0.0.210.oe2203sp4.x86_64.rpm kernel-headers-5.10.0-307.0.0.210.oe2203sp4.x86_64.rpm kernel-source-5.10.0-307.0.0.210.oe2203sp4.x86_64.rpm kernel-tools-5.10.0-307.0.0.210.oe2203sp4.x86_64.rpm kernel-tools-debuginfo-5.10.0-307.0.0.210.oe2203sp4.x86_64.rpm kernel-tools-devel-5.10.0-307.0.0.210.oe2203sp4.x86_64.rpm perf-5.10.0-307.0.0.210.oe2203sp4.x86_64.rpm perf-debuginfo-5.10.0-307.0.0.210.oe2203sp4.x86_64.rpm python3-perf-5.10.0-307.0.0.210.oe2203sp4.x86_64.rpm python3-perf-debuginfo-5.10.0-307.0.0.210.oe2203sp4.x86_64.rpm kernel-5.10.0-307.0.0.210.oe2203sp4.src.rpm bpftool-5.10.0-307.0.0.210.oe2203sp4.aarch64.rpm bpftool-debuginfo-5.10.0-307.0.0.210.oe2203sp4.aarch64.rpm kernel-5.10.0-307.0.0.210.oe2203sp4.aarch64.rpm kernel-debuginfo-5.10.0-307.0.0.210.oe2203sp4.aarch64.rpm kernel-debugsource-5.10.0-307.0.0.210.oe2203sp4.aarch64.rpm kernel-devel-5.10.0-307.0.0.210.oe2203sp4.aarch64.rpm kernel-headers-5.10.0-307.0.0.210.oe2203sp4.aarch64.rpm kernel-source-5.10.0-307.0.0.210.oe2203sp4.aarch64.rpm kernel-tools-5.10.0-307.0.0.210.oe2203sp4.aarch64.rpm kernel-tools-debuginfo-5.10.0-307.0.0.210.oe2203sp4.aarch64.rpm kernel-tools-devel-5.10.0-307.0.0.210.oe2203sp4.aarch64.rpm perf-5.10.0-307.0.0.210.oe2203sp4.aarch64.rpm perf-debuginfo-5.10.0-307.0.0.210.oe2203sp4.aarch64.rpm python3-perf-5.10.0-307.0.0.210.oe2203sp4.aarch64.rpm python3-perf-debuginfo-5.10.0-307.0.0.210.oe2203sp4.aarch64.rpm A vulnerability exists in the RDMA/umad component of the Linux kernel when processing user-space data. The ib_umad_write function calculates data_len based on user-controlled count and MAD header sizes. When a mismatched user MAD header size and RMPP header length are provided, data_len can become negative and be passed to the ib_create_send_mad() function. This can cause subsequent padding calculations to exceed the segment size, ultimately triggering an out-of-bounds memory write (memset) in the alloc_send_rmpp_list() function. An attacker could potentially exploit this vulnerability to cause kernel memory corruption, affecting system stability and confidentiality. 2026-04-03 CVE-2026-23243 openEuler-22.03-LTS-SP4 High 7.3 AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H kernel security update 2026-04-03 https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-1831 In the Linux kernel, the following vulnerability has been resolved: x86/efi: defer freeing of boot services memory efi_free_boot_services() frees memory occupied by EFI_BOOT_SERVICES_CODE and EFI_BOOT_SERVICES_DATA using memblock_free_late(). There are two issue with that: memblock_free_late() should be used for memory allocated with memblock_alloc() while the memory reserved with memblock_reserve() should be freed with free_reserved_area(). More acutely, with CONFIG_DEFERRED_STRUCT_PAGE_INIT=y efi_free_boot_services() is called before deferred initialization of the memory map is complete. Benjamin Herrenschmidt reports that this causes a leak of ~140MB of RAM on EC2 t3a.nano instances which only have 512MB or RAM. If the freed memory resides in the areas that memory map for them is still uninitialized, they won't be actually freed because memblock_free_late() calls memblock_free_pages() and the latter skips uninitialized pages. Using free_reserved_area() at this point is also problematic because __free_page() accesses the buddy of the freed page and that again might end up in uninitialized part of the memory map. Delaying the entire efi_free_boot_services() could be problematic because in addition to freeing boot services memory it updates efi.memmap without any synchronization and that's undesirable late in boot when there is concurrency. More robust approach is to only defer freeing of the EFI boot services memory. Split efi_free_boot_services() in two. First efi_unmap_boot_services() collects ranges that should be freed into an array then efi_free_boot_services() later frees them after deferred init is complete. 2026-04-03 CVE-2026-23352 openEuler-22.03-LTS-SP4 Medium 5.5 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H kernel security update 2026-04-03 https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-1831 In the Linux kernel, a vulnerability has been resolved in Squashfs component: check metadata block offset is within range. Syzkaller reports a "general protection fault in squashfs_copy_data". This is ultimately caused by a corrupted index look-up table, which produces a negative metadata block offset. This is subsequently passed to squashfs_copy_data (via squashfs_read_metadata) where the negative offset causes an out of bounds access. The fix is to check that the offset is within range in squashfs_read_metadata. This will trap this and other cases. 2026-04-03 CVE-2026-23388 openEuler-22.03-LTS-SP4 Medium 6.6 AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H kernel security update 2026-04-03 https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-1831