{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2025-39723 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-39723 is a high-severity vulnerability in Linux kernel, published on 5 Sep 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2025-39723 and fix it if it is affected.\n\nWhat it is: CVE-2025-39723 is a high-severity vulnerability in Linux kernel, published on 5 Sep 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.\nExploitation: There is no known exploitation of CVE-2025-39723 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-2025-39723/ (Markdown: https://insights.sbomify.com/CVE-2025-39723/index.md)","id":"CVE-2025-39723","markdown":"https://insights.sbomify.com/CVE-2025-39723/index.md","name":"CVE-2025-39723","record":{"aliases":["BELL-CVE-2025-39723","DEBIAN-CVE-2025-39723","GHSA-6r55-jr8w-3x3r","ROOT-OS-DEBIAN-13-CVE-2025-39723","UBUNTU-CVE-2025-39723"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Linux kernel","requires_auth":"none","summary":"A flaw in Linux kernel netfs unbuffered write error handling causes a NULL pointer dereference and kernel oops when all subrequests fail.","user_interaction":"required","vuln_class":"null_dereference"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":7.1,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H","version":"3.1"},"cwes":[{"id":"CWE-787","name":"Out-of-bounds Write"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfs: Fix unbuffered write error handling\n\nIf all the subrequests in an unbuffered write stream fail, the subrequest\ncollector doesn't update the stream-\u003etransferred value and it retains its\ninitial LONG_MAX value.  Unfortunately, if all active streams fail, then we\ntake the smallest value of { LONG_MAX, LONG_MAX, ... } as the value to set\nin wreq-\u003etransferred - which is then returned from -\u003ewrite_iter().\n\nLONG_MAX was chosen as the initial value so that all the streams can be\nquickly assessed by taking the smallest value of all stream-\u003etransferred -\nbut this only works if we've set any of them.\n\nFix this by adding a flag to indicate whether the value in\nstream-\u003etransferred is valid and checking that when we integrate the\nvalues.  stream-\u003etransferred can then be initialised to zero.\n\nThis was found by running the generic/750 xfstest against cifs with\ncache=none.  It splices data to the target file.  Once (if) it has used up\nall the available scratch space, the writes start failing with ENOSPC.\nThis causes -\u003ewrite_iter() to fail.  However, it was returning\nwreq-\u003etransferred, i.e. LONG_MAX, rather than an error (because it thought\nthe amount transferred was non-zero) and iter_file_splice_write() would\nthen try to clean up that amount of pipe bufferage - leading to an oops\nwhen it overran.  The kernel log showed:\n\n    CIFS: VFS: Send error in write = -28\n\nfollowed by:\n\n    BUG: kernel NULL pointer dereference, address: 0000000000000008\n\nwith:\n\n    RIP: 0010:iter_file_splice_write+0x3a4/0x520\n    do_splice+0x197/0x4e0\n\nor:\n\n    RIP: 0010:pipe_buf_release (include/linux/pipe_fs_i.h:282)\n    iter_file_splice_write (fs/splice.c:755)\n\nAlso put a warning check into splice to announce if -\u003ewrite_iter() returned\nthat it had written more than it was asked to.","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":"netfs: Fix unbuffered write error handling","id":"CVE-2025-39723","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"null_dereference","year":"2025"},"n_packages":0,"n_references":3,"next":{"headline":"serial: 8250: fix panic due to PSLVERR","id":"CVE-2025-39724"},"packages":[],"prev":{"headline":"crypto: caam - Prevent crash on suspend with iMX8QM / iMX8ULP","id":"CVE-2025-39722"},"products":["Linux"],"published":"2025-09-05","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":"2026-08-05","vendors":["Linux"]},"summary":"A flaw in Linux kernel netfs unbuffered write error handling causes a NULL pointer dereference and kernel oops when all subrequests fail.","url":"https://insights.sbomify.com/CVE-2025-39723/"}