{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-89666 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-89666 is a vulnerability in Linux, published on 11 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-89666 and fix it if it is affected.\n\nWhat it is: CVE-2026-89666 is a vulnerability in Linux, published on 11 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-89666 in the wild and no public exploit code.\n\nAffected product: Linux. 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-2026-89666/ (Markdown: https://insights.sbomify.com/CVE-2026-89666/index.md)","id":"CVE-2026-89666","markdown":"https://insights.sbomify.com/CVE-2026-89666/index.md","name":"CVE-2026-89666","record":{"aliases":["AZL-100485","BELL-CVE-2026-89666","DEBIAN-CVE-2026-89666","GHSA-55g6-jf39-8gg4","UBUNTU-CVE-2026-89666"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["data_modify"],"network_reachable":"yes","non_default_config":false,"product_category":"Linux kernel NFS server","requires_auth":"low_privilege","summary":"An attacker can corrupt on-disk file metadata by sending out-of-range nanosecond values in NFSv3 requests, leading to incorrect timestamp storage.","user_interaction":"not_required","vuln_class":"integer_overflow"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":null,"severity":null,"source":null,"vector":null,"version":null},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: reject out-of-range nseconds in NFSv3 SETATTR and create ops\n\nA client can send an NFSv3 SETATTR, CREATE, MKDIR, SYMLINK or MKNOD\ncarrying an atime or mtime whose nseconds field is out of range. The\nvalue is well-formed on the wire and decodes cleanly into a valid\nuint32, but it is not a valid timespec64: tv_nsec must be less than\nNSEC_PER_SEC.\n\nNothing in the setattr path clamps it. notify_change() runs the time\nthrough timestamp_truncate(), which does not reduce tv_nsec below\nNSEC_PER_SEC when the filesystem supports nanosecond granularity\n(s_time_gran == 1), and the inode atime/mtime setters store it verbatim\n(only ctime is normalized, via inode_set_ctime_to_ts()). The\nun-normalized value then corrupts on-disk metadata: ext4's\next4_encode_extra_time() shifts tv_nsec left by EXT4_EPOCH_BITS, which\noverflows the 32-bit extra field and clobbers the seconds-epoch bits, so\nthe stored seconds (and thus the year) are wrong on read-back. XFS with\nbigtime mis-stores the timestamp for the same reason.\n\nValidate the client-supplied atime/mtime in the proc handlers and return\nNFS3ERR_INVAL before anything is changed. RFC 1813 lists NFS3ERR_INVAL\nfor SETATTR and describes it as the error for a value the server 'can\nnot store ... in its own representation'; the client maps it to EINVAL.\n\nChecking in the proc handlers, rather than in nfsd_setattr(), keeps the\nrejection in front of object creation. The create operations create the\nobject before nfsd_create_setattr() runs, so a late failure would leave\nthe new object behind and turn a non-idempotent request into a namespace\nchange that reports failure. The check is therefore done up front, for\nthe create operations before the object is created.\n\ntv_nsec is a long, so the comparison casts it to unsigned long (the same\nwidth) rather than to u32, matching timespec64_valid(). A u32 cast would\ntruncate on 64-bit; the unsigned long cast also rejects a value that\nbecame negative when an out-of-range u32 wire nseconds was assigned to a\n32-bit long.\n\nOnly client-supplied times are checked: SET_TO_SERVER_TIME requests\ncarry no client value. The sattrguard3 ctime is deliberately left alone:\nan out-of-range guard simply never matches the object's ctime and yields\nNFS3ERR_NOT_SYNC via the existing guardtime comparison, which is the\nprotocol-correct outcome rather than rejecting the request.","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":"nfsd: reject out-of-range nseconds in NFSv3 SETATTR and create ops","id":"CVE-2026-89666","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"integer_overflow","year":"2026"},"n_packages":0,"n_references":5,"next":{"headline":"nfsd: close shrinker/GC/fsnotify vs per-net shutdown race in filecache","id":"CVE-2026-89667"},"packages":[],"prev":{"headline":"nfsd: reject out-of-range useconds in NFSv2 SETATTR/CREATE","id":"CVE-2026-89665"},"products":["Linux"],"published":"2026-09-11","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-10-21","vendors":["Linux"]},"summary":"An attacker can corrupt on-disk file metadata by sending out-of-range nanosecond values in NFSv3 requests, leading to incorrect timestamp storage.","url":"https://insights.sbomify.com/CVE-2026-89666/"}