{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-23383", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-01-13T15:37:46.007Z", "datePublished": "2026-03-25T10:28:02.126Z", "dateUpdated": "2026-08-05T12:21:21.051Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:21:21.051Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing\n\nstruct bpf_plt contains a u64 target field. Currently, the BPF JIT\nallocator requests an alignment of 4 bytes (sizeof(u32)) for the JIT\nbuffer.\n\nBecause the base address of the JIT buffer can be 4-byte aligned (e.g.,\nending in 0x4 or 0xc), the relative padding logic in build_plt() fails\nto ensure that target lands on an 8-byte boundary.\n\nThis leads to two issues:\n1. UBSAN reports misaligned-access warnings when dereferencing the\n structure.\n2. More critically, target is updated concurrently via WRITE_ONCE() in\n bpf_arch_text_poke() while the JIT'd code executes ldr. On arm64,\n 64-bit loads/stores are only guaranteed to be single-copy atomic if\n they are 64-bit aligned. A misaligned target risks a torn read,\n causing the JIT to jump to a corrupted address.\n\nFix this by increasing the allocation alignment requirement to 8 bytes\n(sizeof(u64)) in bpf_jit_binary_pack_alloc(). This anchors the base of\nthe JIT buffer to an 8-byte boundary, allowing the relative padding math\nin build_plt() to correctly align the target field." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - BPF is accessed via the bpf() syscall, requiring local system access. There is no remote or adjacent network path to trigger BPF program loading or trampoline attachment.\nAC:L - The attacker controls both sides of the race — they load the BPF program (creating the misaligned PLT) and trigger the text_poke (by attaching a trampoline). The ~50% misalignment chance is overcome by loading multiple programs. No conditions beyond attacker control are needed.\nPR:L - While CAP_BPF and CAP_PERFMON are required, the BPF token delegation mechanism allows these capabilities to be granted to users in user namespaces. This is a supported, reasonable deployment scenario for containerized BPF workloads.\nUI:N - No user interaction is required. The attacker independently loads BPF programs and attaches trampolines.\nS:U - The vulnerability results in kernel-level control flow corruption within the same security authority. No VM escape, IOMMU bypass, or sandbox boundary crossing occurs.\nC:H - The torn PLT target causes a kernel-mode jump to a corrupted address, which is a control-flow hijack in kernel context. This could be leveraged to read arbitrary kernel memory through code execution.\nI:H - A kernel-mode jump to a corrupted address constitutes control-flow hijacking that could be leveraged for arbitrary code execution in kernel context, enabling arbitrary memory writes.\nA:H - Jumping to a corrupted address in kernel mode will almost certainly cause a kernel panic/oops, resulting in complete denial of service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/arm64/net/bpf_jit_comp.c" ], "versions": [ { "version": "b2ad54e1533e91449cb2a371e034942bd7882b58", "lessThan": "80ad264da02cc4aee718e799c2b79f0f834673dc", "status": "affected", "versionType": "git" }, { "version": "b2ad54e1533e91449cb2a371e034942bd7882b58", "lessThan": "519b1ad91de5bf7a496f2b858e9212db6328e1de", "status": "affected", "versionType": "git" }, { "version": "b2ad54e1533e91449cb2a371e034942bd7882b58", "lessThan": "66959ed481a474eaae278c7f6860a2a9b188a4d6", "status": "affected", "versionType": "git" }, { "version": "b2ad54e1533e91449cb2a371e034942bd7882b58", "lessThan": "ef06fd16d48704eac868441d98d4ef083d8f3d07", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/arm64/net/bpf_jit_comp.c" ], "versions": [ { "version": "6.0", "status": "affected" }, { "version": "0", "lessThan": "6.0", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.77", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.17", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.7", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.12.77" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.18.17" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.19.7" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "7.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/80ad264da02cc4aee718e799c2b79f0f834673dc" }, { "url": "https://git.kernel.org/stable/c/519b1ad91de5bf7a496f2b858e9212db6328e1de" }, { "url": "https://git.kernel.org/stable/c/66959ed481a474eaae278c7f6860a2a9b188a4d6" }, { "url": "https://git.kernel.org/stable/c/ef06fd16d48704eac868441d98d4ef083d8f3d07" } ], "title": "bpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing", "x_generator": { "engine": "bippy-1.2.0" } } } }