{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-43009 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-43009 is a high-severity vulnerability in Linux kernel, published on 1 May 2026. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-43009 and fix it if it is affected.\n\nWhat it is: CVE-2026-43009 is a high-severity vulnerability in Linux kernel, published on 1 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-43009 in the wild and no public exploit code.\n\nAffected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-43009/ (Markdown: https://insights.sbomify.com/CVE-2026-43009/index.md)","id":"CVE-2026-43009","markdown":"https://insights.sbomify.com/CVE-2026-43009/index.md","name":"CVE-2026-43009","record":{"aliases":["AZL-85407","BELL-CVE-2026-43009","DEBIAN-CVE-2026-43009","GHSA-c84q-5rwr-h9h9","ROOT-OS-DEBIAN-12-CVE-2026-43009","ROOT-OS-DEBIAN-13-CVE-2026-43009","ROOT-OS-UBUNTU-2204-CVE-2026-43009","ROOT-OS-UBUNTU-2404-CVE-2026-43009","UBUNTU-CVE-2026-43009"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["other"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel BPF","requires_auth":"low_privilege","summary":"Incorrect BPF verifier pruning due to atomic fetch precision tracking flaws may allow bypassing security checks or undefined behavior.","user_interaction":"not_required","vuln_class":"other"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":7.8,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"cwes":[{"id":"CWE-682","name":"Incorrect Calculation"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix incorrect pruning due to atomic fetch precision tracking\n\nWhen backtrack_insn encounters a BPF_STX instruction with BPF_ATOMIC\nand BPF_FETCH, the src register (or r0 for BPF_CMPXCHG) also acts as\na destination, thus receiving the old value from the memory location.\n\nThe current backtracking logic does not account for this. It treats\natomic fetch operations the same as regular stores where the src\nregister is only an input. This leads the backtrack_insn to fail to\npropagate precision to the stack location, which is then not marked\nas precise!\n\nLater, the verifier's path pruning can incorrectly consider two states\nequivalent when they differ in terms of stack state. Meaning, two\nbranches can be treated as equivalent and thus get pruned when they\nshould not be seen as such.\n\nFix it as follows: Extend the BPF_LDX handling in backtrack_insn to\nalso cover atomic fetch operations via is_atomic_fetch_insn() helper.\nWhen the fetch dst register is being tracked for precision, clear it,\nand propagate precision over to the stack slot. For non-stack memory,\nthe precision walk stops at the atomic instruction, same as regular\nBPF_LDX. This covers all fetch variants.\n\nBefore:\n\n  0: (b7) r1 = 8                        ; R1=8\n  1: (7b) *(u64 *)(r10 -8) = r1         ; R1=8 R10=fp0 fp-8=8\n  2: (b7) r2 = 0                        ; R2=0\n  3: (db) r2 = atomic64_fetch_add((u64 *)(r10 -8), r2)          ; R2=8 R10=fp0 fp-8=mmmmmmmm\n  4: (bf) r3 = r10                      ; R3=fp0 R10=fp0\n  5: (0f) r3 += r2\n  mark_precise: frame0: last_idx 5 first_idx 0 subseq_idx -1\n  mark_precise: frame0: regs=r2 stack= before 4: (bf) r3 = r10\n  mark_precise: frame0: regs=r2 stack= before 3: (db) r2 = atomic64_fetch_add((u64 *)(r10 -8), r2)\n  mark_precise: frame0: regs=r2 stack= before 2: (b7) r2 = 0\n  6: R2=8 R3=fp8\n  6: (b7) r0 = 0                        ; R0=0\n  7: (95) exit\n\nAfter:\n\n  0: (b7) r1 = 8                        ; R1=8\n  1: (7b) *(u64 *)(r10 -8) = r1         ; R1=8 R10=fp0 fp-8=8\n  2: (b7) r2 = 0                        ; R2=0\n  3: (db) r2 = atomic64_fetch_add((u64 *)(r10 -8), r2)          ; R2=8 R10=fp0 fp-8=mmmmmmmm\n  4: (bf) r3 = r10                      ; R3=fp0 R10=fp0\n  5: (0f) r3 += r2\n  mark_precise: frame0: last_idx 5 first_idx 0 subseq_idx -1\n  mark_precise: frame0: regs=r2 stack= before 4: (bf) r3 = r10\n  mark_precise: frame0: regs=r2 stack= before 3: (db) r2 = atomic64_fetch_add((u64 *)(r10 -8), r2)\n  mark_precise: frame0: regs= stack=-8 before 2: (b7) r2 = 0\n  mark_precise: frame0: regs= stack=-8 before 1: (7b) *(u64 *)(r10 -8) = r1\n  mark_precise: frame0: regs=r1 stack= before 0: (b7) r1 = 8\n  6: R2=8 R3=fp8\n  6: (b7) r0 = 0                        ; R0=0\n  7: (95) exit","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"bpf: Fix incorrect pruning due to atomic fetch precision tracking","id":"CVE-2026-43009","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"other","year":"2026"},"n_packages":0,"n_references":5,"next":{"headline":"bpf: Reject sleepable kprobe_multi programs at attach time","id":"CVE-2026-43010"},"packages":[],"prev":{"headline":"gpio: qixis-fpga: Fix error handling for devm_regmap_init_mmio()","id":"CVE-2026-43008"},"products":["Linux"],"published":"2026-05-01","related":[{"cvss_score":8.8,"headline":"Linux Kernel Out-of-Bounds Write","id":"CVE-2026-53266","kev_date_added":"2026-09-18","published":"2026-06-25"},{"cvss_score":8.8,"headline":"Linux Kernel Improper Input Validation","id":"CVE-2013-6282","kev_date_added":"2022-09-15","published":"2013-11-19"},{"cvss_score":8.4,"headline":"Linux Kernel Heap-Based Buffer Overflow","id":"CVE-2022-0185","kev_date_added":"2024-08-21","published":"2022-02-11"},{"cvss_score":8.4,"headline":"Linux Kernel Privilege Escalation","id":"CVE-2013-2094","kev_date_added":"2022-09-15","published":"2013-05-14"},{"cvss_score":7.8,"headline":"Linux Kernel Unspecified","id":"CVE-2026-53362","kev_date_added":"2026-08-27","published":"2026-07-04"},{"cvss_score":7.8,"headline":"Linux Kernel Missing Initialization of a Variable","id":"CVE-2026-46300","kev_date_added":"2026-10-28","published":"2026-05-23"},{"cvss_score":7.8,"headline":"Linux Kernel Race Condition","id":"CVE-2025-39964","kev_date_added":"2026-09-18","published":"2025-10-13"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-10-21","vendors":["Linux"]},"summary":"Incorrect BPF verifier pruning due to atomic fetch precision tracking flaws may allow bypassing security checks or undefined behavior.","url":"https://insights.sbomify.com/CVE-2026-43009/"}