{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-23157 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-23157 is a medium-severity denial of service vulnerability in Linux kernel, published on 14 Feb 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-2026-23157 and fix it if it is affected.\n\nWhat it is: CVE-2026-23157 is a medium-severity denial of service vulnerability in Linux kernel, published on 14 Feb 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-2026-23157 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-2026-23157/ (Markdown: https://insights.sbomify.com/CVE-2026-23157/index.md)","id":"CVE-2026-23157","markdown":"https://insights.sbomify.com/CVE-2026-23157/index.md","name":"CVE-2026-23157","record":{"aliases":["AZL-77820","BELL-CVE-2026-23157","DEBIAN-CVE-2026-23157","GHSA-pw2v-cmfh-x2p3","ROOT-OS-DEBIAN-11-CVE-2026-23157","ROOT-OS-DEBIAN-12-CVE-2026-23157","ROOT-OS-DEBIAN-13-CVE-2026-23157","ROOT-OS-UBUNTU-2204-CVE-2026-23157","ROOT-OS-UBUNTU-2404-CVE-2026-23157","UBUNTU-CVE-2026-23157"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A flaw in the Linux kernel's btrfs filesystem can cause system hangs and kernel coredumps when dirty page throttling interacts with internal writeback thresholds.","user_interaction":"not_required","vuln_class":"denial_of_service"},"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-667","name":"Improper Locking"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: do not strictly require dirty metadata threshold for metadata writepages\n\n[BUG]\nThere is an internal report that over 1000 processes are\nwaiting at the io_schedule_timeout() of balance_dirty_pages(), causing\na system hang and trigger a kernel coredump.\n\nThe kernel is v6.4 kernel based, but the root problem still applies to\nany upstream kernel before v6.18.\n\n[CAUSE]\nFrom Jan Kara for his wisdom on the dirty page balance behavior first.\n\n  This cgroup dirty limit was what was actually playing the role here\n  because the cgroup had only a small amount of memory and so the dirty\n  limit for it was something like 16MB.\n\n  Dirty throttling is responsible for enforcing that nobody can dirty\n  (significantly) more dirty memory than there's dirty limit. Thus when\n  a task is dirtying pages it periodically enters into balance_dirty_pages()\n  and we let it sleep there to slow down the dirtying.\n\n  When the system is over dirty limit already (either globally or within\n  a cgroup of the running task), we will not let the task exit from\n  balance_dirty_pages() until the number of dirty pages drops below the\n  limit.\n\n  So in this particular case, as I already mentioned, there was a cgroup\n  with relatively small amount of memory and as a result with dirty limit\n  set at 16MB. A task from that cgroup has dirtied about 28MB worth of\n  pages in btrfs btree inode and these were practically the only dirty\n  pages in that cgroup.\n\nSo that means the only way to reduce the dirty pages of that cgroup is\nto writeback the dirty pages of btrfs btree inode, and only after that\nthose processes can exit balance_dirty_pages().\n\nNow back to the btrfs part, btree_writepages() is responsible for\nwriting back dirty btree inode pages.\n\nThe problem here is, there is a btrfs internal threshold that if the\nbtree inode's dirty bytes are below the 32M threshold, it will not\ndo any writeback.\n\nThis behavior is to batch as much metadata as possible so we won't write\nback those tree blocks and then later re-COW them again for another\nmodification.\n\nThis internal 32MiB is higher than the existing dirty page size (28MiB),\nmeaning no writeback will happen, causing a deadlock between btrfs and\ncgroup:\n\n- Btrfs doesn't want to write back btree inode until more dirty pages\n\n- Cgroup/MM doesn't want more dirty pages for btrfs btree inode\n  Thus any process touching that btree inode is put into sleep until\n  the number of dirty pages is reduced.\n\nThanks Jan Kara a lot for the analysis of the root cause.\n\n[ENHANCEMENT]\nSince kernel commit b55102826d7d (\"btrfs: set AS_KERNEL_FILE on the\nbtree_inode\"), btrfs btree inode pages will only be charged to the root\ncgroup which should have a much larger limit than btrfs' 32MiB\nthreshold.\nSo it should not affect newer kernels.\n\nBut for all current LTS kernels, they are all affected by this problem,\nand backporting the whole AS_KERNEL_FILE may not be a good idea.\n\nEven for newer kernels I still think it's a good idea to get\nrid of the internal threshold at btree_writepages(), since for most cases\ncgroup/MM has a better view of full system memory usage than btrfs' fixed\nthreshold.\n\nFor internal callers using btrfs_btree_balance_dirty() since that\nfunction is already doing internal threshold check, we don't need to\nbother them.\n\nBut for external callers of btree_writepages(), just respect their\nrequests and write back whatever they want, ignoring the internal\nbtrfs threshold to avoid such deadlock on btree inode dirty page\nbalancing.","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":"btrfs: do not strictly require dirty metadata threshold for metadata writepages","id":"CVE-2026-23157","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"denial_of_service","year":"2026"},"n_packages":0,"n_references":6,"next":{"headline":"gpio: virtuser: fix UAF in configfs release path","id":"CVE-2026-23158"},"packages":[],"prev":{"headline":"efivarfs: fix error propagation in efivar_entry_get()","id":"CVE-2026-23156"},"products":["Linux"],"published":"2026-02-14","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":"2026-10-15","vendors":["Linux"]},"summary":"A flaw in the Linux kernel's btrfs filesystem can cause system hangs and kernel coredumps when dirty page throttling interacts with internal writeback thresholds.","url":"https://insights.sbomify.com/CVE-2026-23157/"}