{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-98980 in the wild and no public exploit code.","fix":"Upgrade to a fixed version.","what":"CVE-2026-98980 is a high-severity vulnerability in Linux, published on 23 Oct 2026."},"fix_prompt":"Check this codebase for CVE-2026-98980 and fix it if it is affected.\n\nWhat it is: CVE-2026-98980 is a high-severity vulnerability in Linux, published on 23 Oct 2026. \nExploitation: There is no known exploitation of CVE-2026-98980 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-2026-98980/ (Markdown: https://insights.sbomify.com/CVE-2026-98980/index.md)","id":"CVE-2026-98980","markdown":"https://insights.sbomify.com/CVE-2026-98980/index.md","name":"CVE-2026-98980","record":{"aliases":["AZL-110813","BELL-CVE-2026-98980","DEBIAN-CVE-2026-98980","GHSA-r8cp-fx7r-5fxq","UBUNTU-CVE-2026-98980"],"analysis":null,"analysis_generated_by":null,"assigner":"Linux","cpe":[],"cvss":{"score":8.8,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","version":"3.1"},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnamei: don't reveal overmounted entries in refwalk\n\nIn rcuwalk the dentry is validated before it is accepted. step_into()\nstep_into() rechecks d_seq and __follow_mount_rcu() rechecks mount_lock.\nAn entry that gets unlinked in between causes the lookup to retry and\nmiss.\n\nA refwalk doesn't do this. lookup_fast() takes a reference on the hashed\ndentry and simply accepts it. So an unlink that happens after the\nreference was taken isn't seen by refwalk. That's fine for a simple\nfile. We just happened to open it before it was unlinked, no problem.\n\nFor a mountpoint and specifically a locked mountpoint it very much\nisn't. The unlink detaches all mounts and then removes the name. Any\nrefwalk that hasn't traversed the mounts yet simply reveals the\nunderlying entry. It's a very narrow window but it can be hit:\n\n  reads of a covered file in 60 s, 3 walkers, ~15000 unlinks\n    no widening            27\n    that step + 200 us   3741\n\nSee the appended patch for a more reliable reproducer.\n\nSo check the entry after step_into(). unlink(), rmdir() and rename()\nmark the dentry with dont_mount() before they detach the mounts and\nremove the dentry.\n\nSo a dentry that is marked with DCACHE_CANT_MOUNT and is unhashed by the\ntime its mounts were looked at is a name that was unlinked under the\nrefwalk. DCACHE_CANT_MOUNT is read after the mounts were looked up and\nit is set before they are detached by detach_mounts(). A refwalk that\nmissed the mounts will see DCACHE_CANT_MOUNT.\n\nPlain d_unlinked() is fine. A rename takes the dentry off its hash chain\nbut ___d_drop() leaves d_hash.pprev set. So only __d_drop() and a rename\nover the dentry unhash it. The only move that flips IS_ROOT splices in a\ndisconnected alias. That doesn't have DCACHE_CANT_MOUNT set.\n\nAdd the to step_into_slowpath(). \"..\" and LOOKUP_DOWN may legitimately\nland on an unhashed directory. A refwalk that crossed onto a mount has\npath.mnt different from nd-\u003epath.mnt. A dentry that a filesystem dropped\non its own (d_invalidate(), d_drop()) doesn't have the flag set and is\ntreated as before.\n\n  // SPDX-License-Identifier: GPL-2.0\n  /*\n   * unlink_covered: unlink a file that is a mountpoint in a detached copy of\n   * its mount, against walkers that open it through that copy.\n   *\n   * A is a tmpfs with the file f1 (content SECRET_F) and the plain file\n   * MARK_A. A' is an open_tree(OPEN_TREE_CLONE) copy of A with MARK_A bound\n   * on A'/f1, held through an O_PATH fd on its root once the tree fd is\n   * closed. Walkers open f1 through that fd while the driver unlinks A/f1,\n   * where nothing is mounted on it. A walker may read MARK_A or get ENOENT.\n   * A read of SECRET_F is a hit: the name was found after its mount was\n   * gone. The lockless walks use openat2(RESOLVE_CACHED).\n   *\n   * usage: unlink_covered [-t seconds] [-w walkers]\n   */\n  #ifndef _GNU_SOURCE\n  #define _GNU_SOURCE\n  #endif\n  #include \u003cerrno.h\u003e\n  #include \u003cfcntl.h\u003e\n  #include \u003cpthread.h\u003e\n  #include \u003cstdatomic.h\u003e\n  #include \u003cstdio.h\u003e\n  #include \u003cstdlib.h\u003e\n  #include \u003cstring.h\u003e\n  #include \u003cunistd.h\u003e\n  #include \u003csys/mount.h\u003e\n  #include \u003csys/stat.h\u003e\n  #include \u003csys/syscall.h\u003e\n  #include \u003clinux/openat2.h\u003e\n\n  #ifndef __NR_open_tree\n  #define __NR_open_tree 428\n  #endif\n  #ifndef __NR_move_mount\n  #define __NR_move_mount 429\n  #endif\n  #ifndef __NR_openat2\n  #define __NR_openat2 437\n  #endif\n  #ifndef OPEN_TREE_CLONE\n  #define OPEN_TREE_CLONE 1\n  #endif\n  #ifndef OPEN_TREE_CLOEXEC\n  #define OPEN_TREE_CLOEXEC O_CLOEXEC\n  #endif\n  #ifndef MOVE_MOUNT_F_EMPTY_PATH\n  #define MOVE_MOUNT_F_EMPTY_PATH 0x00000004\n  #endif\n\n  #define WORK \"/tmp/uc\"\n  #define ADIR WORK \"/A\"\n\n  static int duration = 60, nwalkers = 3;\n  static atomic_int stop, writer_waiting;\n  static pthread_rwlock_t cur_lock = PTHREAD_RWLOCK_INITIALIZER;\n  static int cur_fd = -1;\t\t/* the root of A', -1 while there is none */\n  static atomic_long n_unlink, n_walk, n_mark, n_enoent, n_othe\n---truncated---","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":"namei: don't reveal overmounted entries in refwalk","id":"CVE-2026-98980","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":null,"year":"2026"},"n_packages":0,"n_references":4,"next":{"headline":"namespace: unhash a dentry before detaching the mounts on it","id":"CVE-2026-98981"},"packages":[],"prev":{"headline":"namespace: refuse an automount below a mount that is in no namespace","id":"CVE-2026-98979"},"products":["Linux"],"published":"2026-10-23","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-10-24","vendors":["Linux"]},"summary":null,"url":"https://insights.sbomify.com/CVE-2026-98980/"}