A TOCTOU (Time-of-Check Time-of-Use) vulnerability in GNU tar's incremental dumpdir 'X' rename handling allows a local attacker with write access to a directory being backed up to influence the restore process if the attacker has access to the system where the restore is being performed. During restoration, files or directories may be created, renamed or overwritten outside the intended extraction directory. This could lead to unauthorized file modification or, in some cases, privilege escalation. Exploitation does not require the attacker to modify or craft the archive, and standard backup and restore workflows—including extracting into a newly created directory without using the -P option do not mitigate the issue.

The remote Fedora 45 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-ee1eb89e7b advisory.

    Fix CVE-2026-5704, CVE-2026-18508, CVE-2026-18477, and a regression in the fix for CVE-2025-45582.


Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote RockyLinux 10 host has packages installed that are affected by multiple vulnerabilities as referenced in the RLSA-2026:61586 advisory.

    * tar: tar: Hidden file injection via crafted archives (CVE-2026-5704)

    * tar: tar: TOCTOU in incremental dumpdir 'X' rename handling allows restore path escape (CVE-2026-18477)

    * tar: tar: --one-top-level hardlink targets not confined to top-level directory enabling arbitrary file     overwrite (CVE-2026-18508)

    Bug Fix(es) and Enhancement(s):

    * tar: --one-top-level with absolute path fails (JIRA:Rocky Linux-143906)

Tenable has extracted the preceding description block directly from the RockyLinux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Fedora 44 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-044e56d9ff advisory.

    Fix build with libacl 2.4.0, fix CVE-2026-5704, CVE-2026-18508, CVE-2026-18477, and a regression in the     fix for CVE-2025-45582.

Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Oracle Linux 10 host has a package installed that is affected by multiple vulnerabilities as referenced in the ELSA-2026-615860 advisory.

    - Backport upstream patches for CVE-2026-18477, fixes a bug       where incremental restore with cyclic renames between backups       may create a temporary directory at an archive-controlled path       outside the extraction tree.
      The fix for CVE-2025-45582 already prevents exploiting       this problem, so it is more a correctness and hardening change.
    - Backport upstream fix for CVE-2026-5704 (file injection hidden from -t)
    - Fix --one-top-level with absolute path (broken by the CVE-2025-45582 fix)       Also fixes CVE-2026-18508 (escape from --one-top-level via hardlinks).

Tenable has extracted the preceding description block directly from the Oracle Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote AlmaLinux 10 host has a package installed that is affected by multiple vulnerabilities as referenced in the ALSA-2026:61586 advisory.

    * tar: tar: Hidden file injection via crafted archives (CVE-2026-5704)
      * tar: tar: TOCTOU in incremental dumpdir 'X' rename handling allows restore path escape     (CVE-2026-18477)
      * tar: tar: --one-top-level hardlink targets not confined to top-level directory enabling arbitrary file     overwrite (CVE-2026-18508)


    Bug Fix(es) and Enhancement(s):

      * tar: --one-top-level with absolute path fails (JIRA:AlmaLinux-143906)

Tenable has extracted the preceding description block directly from the AlmaLinux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Oracle Linux 9 host has a package installed that is affected by multiple vulnerabilities as referenced in the ELSA-2026-615810 advisory.

    - Backport upstream patches for CVE-2026-18477, fixes a bug       where incremental restore with cyclic renames between backups       may create a temporary directory at an archive-controlled path       outside the extraction tree.
      The fix for CVE-2025-45582 already prevents exploiting       this problem, so it is more a correctness and hardening change.
    - Backport upstream fix for CVE-2026-5704 (file injection hidden from -t)
    - Fix --one-top-level with absolute path (broken by the CVE-2025-45582 fix)       Also fixes CVE-2026-18508 (escape from --one-top-level via hardlinks).

Tenable has extracted the preceding description block directly from the Oracle Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote MiracleLinux 9 host has a package installed that is affected by multiple vulnerabilities as referenced in the AXSA:2026-1733:03 advisory.

    * tar: tar: Hidden file injection via crafted archives (CVE-2026-5704)
      * tar: tar: TOCTOU in incremental dumpdir 'X' rename handling allows restore path escape     (CVE-2026-18477)
      * tar: tar: --one-top-level hardlink targets not confined to top-level directory enabling arbitrary file     overwrite (CVE-2026-18508)

Tenable has extracted the preceding description block directly from the MiracleLinux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 10 host has a package installed that is affected by multiple vulnerabilities as referenced in the RHSA-2026:61586 advisory.

    The GNU tar program can save multiple files in an archive and restore files from an archive.

    Security Fix(es):

    * tar: tar: Hidden file injection via crafted archives (CVE-2026-5704)

    * tar: tar: TOCTOU in incremental dumpdir 'X' rename handling allows restore path escape (CVE-2026-18477)

    * tar: tar: --one-top-level hardlink targets not confined to top-level directory enabling arbitrary file     overwrite (CVE-2026-18508)

    Bug Fix(es) and Enhancement(s):

    * tar: --one-top-level with absolute path fails (JIRA:RHEL-143906)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote AlmaLinux 9 host has a package installed that is affected by multiple vulnerabilities as referenced in the ALSA-2026:61581 advisory.

    * tar: tar: Hidden file injection via crafted archives (CVE-2026-5704)
      * tar: tar: TOCTOU in incremental dumpdir 'X' rename handling allows restore path escape     (CVE-2026-18477)
      * tar: tar: --one-top-level hardlink targets not confined to top-level directory enabling arbitrary file     overwrite (CVE-2026-18508)


    Bug Fix(es) and Enhancement(s):

      * tar: --one-top-level with absolute path fails [almalinux-9] (JIRA:AlmaLinux-144021)

Tenable has extracted the preceding description block directly from the AlmaLinux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote RockyLinux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RLSA-2026:61581 advisory.

    * tar: tar: Hidden file injection via crafted archives (CVE-2026-5704)

    * tar: tar: TOCTOU in incremental dumpdir 'X' rename handling allows restore path escape (CVE-2026-18477)

    * tar: tar: --one-top-level hardlink targets not confined to top-level directory enabling arbitrary file     overwrite (CVE-2026-18508)

    Bug Fix(es) and Enhancement(s):

    * tar: --one-top-level with absolute path fails [rhel-9] (JIRA:Rocky Linux-144021)

Tenable has extracted the preceding description block directly from the RockyLinux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 9 host has a package installed that is affected by multiple vulnerabilities as referenced in the RHSA-2026:61581 advisory.

    The GNU tar program can save multiple files in an archive and restore files from an archive.

    Security Fix(es):

    * tar: tar: Hidden file injection via crafted archives (CVE-2026-5704)

    * tar: tar: TOCTOU in incremental dumpdir 'X' rename handling allows restore path escape (CVE-2026-18477)

    * tar: tar: --one-top-level hardlink targets not confined to top-level directory enabling arbitrary file     overwrite (CVE-2026-18508)

    Bug Fix(es) and Enhancement(s):

    * tar: --one-top-level with absolute path fails [rhel-9] (JIRA:RHEL-144021)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote CentOS Linux 9 host has a package installed that is affected by multiple vulnerabilities as referenced in the tar-1.34-13.el9 build changelog.

  - A flaw was found in tar. A remote attacker could exploit this vulnerability by crafting a malicious     archive, leading to hidden file injection with fully attacker-controlled content. This bypasses pre-     extraction inspection mechanisms, potentially allowing an attacker to introduce malicious files onto a     system without detection. (CVE-2026-5704)

  - GNU Tar through 1.35 allows file overwrite via directory traversal in crafted TAR archives, with a certain     two-step process. First, the victim must extract an archive that contains a ../ symlink to a critical     directory. Second, the victim must extract an archive that contains a critical file, specified via a     relative pathname that begins with the symlink name and ends with that critical file's name. Here, the     extraction follows the symlink and overwrites the critical file. This bypasses the protection mechanism of     Member name contains '..' that would occur for a single TAR archive that attempted to specify the     critical file via a ../ approach. For example, the first archive can contain x ->     ../../../../../home/victim/.ssh and the second archive can contain x/authorized_keys. This can affect     server applications that automatically extract any number of user-supplied TAR archives, and were relying     on the blocking of traversal. This can also affect software installation processes in which tar xf is     run more than once (e.g., when installing a package can automatically install two dependencies that are     set up as untrusted tarballs instead of official packages). NOTE: the official GNU Tar manual has an     otherwise-empty directory for each tar xf in its Security Rules of Thumb; however, third-party advice     leads users to run tar xf more than once into the same directory. (CVE-2025-45582)

  - A TOCTOU (Time-of-Check Time-of-Use) vulnerability in GNU tar's incremental dumpdir 'X' rename handling     allows a local attacker with write access to a directory being backed up to influence the restore process     if the attacker has access to the system where the restore is being performed. During restoration, files     or directories may be created, renamed or overwritten outside the intended extraction directory. This     could lead to unauthorized file modification or, in some cases, privilege escalation. Exploitation does     not require the attacker to modify or craft the archive, and standard backup and restore     workflowsincluding extracting into a newly created directory without using the -P option do not mitigate     the issue. (CVE-2026-18477)

  - A flaw was found in GNU tar. When extracting an archive with the --one-top-level option, hardlink targets     are not confined to the designated top-level directory and may resolve relative to the extraction working     directory. A crafted archive can create hardlinks that escape the intended boundary and, when combined     with a preexisting symbolic link under the working directory, may allow writing outside that boundary     during a single extraction. (CVE-2026-18508)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - A TOCTOU (Time-of-Check Time-of-Use) vulnerability in GNU tar's incremental dumpdir 'X' rename handling     allows a local attacker with write access to a directory being backed up to influence the restore process     if the attacker has access to the system where the restore is being performed. During restoration, files     or directories may be created, renamed or overwritten outside the intended extraction directory. This     could lead to unauthorized file modification or, in some cases, privilege escalation. Exploitation does     not require the attacker to modify or craft the archive, and standard backup and restore     workflowsincluding extracting into a newly created directory without using the -P option do not mitigate     the issue. (CVE-2026-18477)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
344985	Fedora 45 : tar (2026-ee1eb89e7b)	Nessus	Fedora Local Security Checks	Local	medium
344660	RockyLinux 10 : tar (RLSA-2026:61586)	Nessus	Rocky Linux Local Security Checks	Local	medium
343964	Fedora 44 : tar (2026-044e56d9ff)	Nessus	Fedora Local Security Checks	Local	medium
342714	Oracle Linux 10 : ELSA-2026-61586-0: / tar (ELSA-2026-615860)	Nessus	Oracle Linux Local Security Checks	Local	medium
342429	AlmaLinux 10 : tar (ALSA-2026:61586)	Nessus	Alma Linux Local Security Checks	Local	medium
342415	Oracle Linux 9 : ELSA-2026-61581-0: / tar (ELSA-2026-615810)	Nessus	Oracle Linux Local Security Checks	Local	medium
342414	MiracleLinux 9 : tar-1.34-13.el9_8 (AXSA:2026-1733:03)	Nessus	Miracle Linux Local Security Checks	Local	medium
342231	RHEL 10 : tar (RHSA-2026:61586)	Nessus	Red Hat Local Security Checks	Local	medium
342164	AlmaLinux 9 : tar (ALSA-2026:61581)	Nessus	Alma Linux Local Security Checks	Local	medium
342154	RockyLinux 9 : tar (RLSA-2026:61581)	Nessus	Rocky Linux Local Security Checks	Local	medium
342029	RHEL 9 : tar (RHSA-2026:61581)	Nessus	Red Hat Local Security Checks	Local	medium
339712	CentOS 9 : tar-1.34-13.el9	Nessus	CentOS Local Security Checks	Local	medium
331741	Linux Distros Unpatched Vulnerability : CVE-2026-18477	Nessus	Misc.	Local	medium

Detections

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CVE-2026-18477

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Tenable Plugins

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