{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2025-37821 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-37821 is a medium-severity vulnerability in Linux kernel, published on 8 May 2025. 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-2025-37821 and fix it if it is affected.\n\nWhat it is: CVE-2025-37821 is a medium-severity vulnerability in Linux kernel, published on 8 May 2025. 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-2025-37821 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-2025-37821/ (Markdown: https://insights.sbomify.com/CVE-2025-37821/index.md)","id":"CVE-2025-37821","markdown":"https://insights.sbomify.com/CVE-2025-37821/index.md","name":"CVE-2025-37821","record":{"aliases":["BELL-CVE-2025-37821","DEBIAN-CVE-2025-37821","GHSA-jq2v-j4fw-m4mg","UBUNTU-CVE-2025-37821"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel scheduler","requires_auth":"low_privilege","summary":"A flaw in the Linux kernel EEVDF scheduler allows an integer overflow leading to a system crash, requiring a kernel patch to resolve.","user_interaction":"not_required","vuln_class":"integer_overflow"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":5.5,"severity":"medium","source":"nvd","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-476","name":"NULL Pointer Dereference"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched/eevdf: Fix se-\u003eslice being set to U64_MAX and resulting crash\n\nThere is a code path in dequeue_entities() that can set the slice of a\nsched_entity to U64_MAX, which sometimes results in a crash.\n\nThe offending case is when dequeue_entities() is called to dequeue a\ndelayed group entity, and then the entity's parent's dequeue is delayed.\nIn that case:\n\n1. In the if (entity_is_task(se)) else block at the beginning of\n   dequeue_entities(), slice is set to\n   cfs_rq_min_slice(group_cfs_rq(se)). If the entity was delayed, then\n   it has no queued tasks, so cfs_rq_min_slice() returns U64_MAX.\n2. The first for_each_sched_entity() loop dequeues the entity.\n3. If the entity was its parent's only child, then the next iteration\n   tries to dequeue the parent.\n4. If the parent's dequeue needs to be delayed, then it breaks from the\n   first for_each_sched_entity() loop _without updating slice_.\n5. The second for_each_sched_entity() loop sets the parent's -\u003eslice to\n   the saved slice, which is still U64_MAX.\n\nThis throws off subsequent calculations with potentially catastrophic\nresults. A manifestation we saw in production was:\n\n6. In update_entity_lag(), se-\u003eslice is used to calculate limit, which\n   ends up as a huge negative number.\n7. limit is used in se-\u003evlag = clamp(vlag, -limit, limit). Because limit\n   is negative, vlag \u003e limit, so se-\u003evlag is set to the same huge\n   negative number.\n8. In place_entity(), se-\u003evlag is scaled, which overflows and results in\n   another huge (positive or negative) number.\n9. The adjusted lag is subtracted from se-\u003evruntime, which increases or\n   decreases se-\u003evruntime by a huge number.\n10. pick_eevdf() calls entity_eligible()/vruntime_eligible(), which\n    incorrectly returns false because the vruntime is so far from the\n    other vruntimes on the queue, causing the\n    (vruntime - cfs_rq-\u003emin_vruntime) * load calulation to overflow.\n11. Nothing appears to be eligible, so pick_eevdf() returns NULL.\n12. pick_next_entity() tries to dereference the return value of\n    pick_eevdf() and crashes.\n\nDumping the cfs_rq states from the core dumps with drgn showed tell-tale\nhuge vruntime ranges and bogus vlag values, and I also traced se-\u003eslice\nbeing set to U64_MAX on live systems (which was usually \"benign\" since\nthe rest of the runqueue needed to be in a particular state to crash).\n\nFix it in dequeue_entities() by always setting slice from the first\nnon-empty cfs_rq.","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":"sched/eevdf: Fix se-\u003eslice being set to U64_MAX and resulting crash","id":"CVE-2025-37821","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"integer_overflow","year":"2025"},"n_packages":0,"n_references":3,"next":{"headline":"riscv: uprobes: Add missing fence.i after building the XOL buffer","id":"CVE-2025-37822"},"packages":[],"prev":{"headline":"xen-netfront: handle NULL returned by xdp_convert_buff_to_frame()","id":"CVE-2025-37820"},"products":["Linux"],"published":"2025-05-08","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":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-05-11","vendors":["Linux"]},"summary":"A flaw in the Linux kernel EEVDF scheduler allows an integer overflow leading to a system crash, requiring a kernel patch to resolve.","url":"https://insights.sbomify.com/CVE-2025-37821/"}