libnfs through 6.0.2 before 55c18ea does not validate a string size, leading to an integer overflow during a connection to a crafted NFS server. This occurs in libnfs_zdr_string in lib/libnfs-zdr.c.

The remote Debian 11 / 12 host has packages installed that are affected by a vulnerability as referenced in the dla-4689 advisory.

    - -------------------------------------------------------------------------     Debian LTS Advisory DLA-4689-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/                    Thorsten Alteholz     July 19, 2026                                 https://wiki.debian.org/LTS
    - -------------------------------------------------------------------------

    Package        : libnfs     Version        : 4.0.0-1+deb11u1 4.0.0-1+deb12u1     CVE ID         : CVE-2026-53689     Debian Bug     : 1139731


    An issue has been found in libnfs, am NFS client library.
    The issue is related to to a missing validation of a string size that     might lead to an integer overflow.



    For Debian 11 bullseye, this problem has been fixed in version     4.0.0-1+deb11u1.

    For Debian 12 bookworm, this problem has been fixed in version     4.0.0-1+deb12u1.

    We recommend that you upgrade your libnfs packages.

    For the detailed security status of libnfs please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/libnfs

    Further information about Debian LTS security advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://wiki.debian.org/LTS

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

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

The remote SUSE Linux SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 host has packages installed that are affected by a vulnerability as referenced in the SUSE-SU-2026:2760-1 advisory.

    This update for libnfs fixes the following issue

    - CVE-2026-53689: integer overflow during a connection to a crafted NFS server (bsc#1268135).

    Changes for libnfs:

    - Add libnfs-CVE-2026-53689.patch: ZDR: check the string size for      sanity (bsc#1268135 CVE-2026-53689).

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

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

The remote openSUSE 16 host has packages installed that are affected by a vulnerability as referenced in the openSUSE- SU-2026:21055-1 advisory.

    This update for libnfs fixes the following issue

    - CVE-2026-53689: integer overflow during a connection to a crafted NFS server (bsc#1268135).

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

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

The remote Ubuntu 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS host has packages installed that are affected by a vulnerability as referenced in the USN-8464-1 advisory.

    It was discovered that LIBNFS incorrectly handled certain string sizes when connecting to an NFS server.
    An attacker could use this issue to cause LIBNFS to crash, resulting in a denial of service, or possibly     execute arbitrary code.

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

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

The version of libnfs installed on the remote host is prior to 1.11.0-1. It is, therefore, affected by a vulnerability as referenced in the ALAS2-2026-3367 advisory.

    libnfs through 6.0.2 before 55c18ea does not validate a string size, leading to an integer overflow during     a connection to a crafted NFS server. This occurs in libnfs_zdr_string in lib/libnfs-zdr.c.
    (CVE-2026-53689)

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

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

It is, therefore, affected by a vulnerability as referenced in the ALAS2023-2026-1855 advisory.

    libnfs through 6.0.2 before 55c18ea does not validate a string size, leading to an integer overflow during     a connection to a crafted NFS server. This occurs in libnfs_zdr_string in lib/libnfs-zdr.c.
    (CVE-2026-53689)

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

Note that Nessus has not tested for this issue 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.

  - libnfs through 6.0.2 before 55c18ea does not validate a string size, leading to an integer overflow during     a connection to a crafted NFS server. This occurs in libnfs_zdr_string in lib/libnfs-zdr.c.
    (CVE-2026-53689)

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

ID	Name	Product	Family	Severity
327822	Debian dla-4689 : libnfs-dev - security update	Nessus	Debian Local Security Checks	high
325366	SUSE SLED15 / SLES15 Security Update : libnfs (SUSE-SU-2026:2760-1)	Nessus	SuSE Local Security Checks	high
324074	openSUSE 16 Security Update : libnfs (openSUSE-SU-2026:21055-1)	Nessus	SuSE Local Security Checks	high
322482	Ubuntu 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS : LIBNFS vulnerability (USN-8464-1)	Nessus	Ubuntu Local Security Checks	high
322104	Amazon Linux 2 : libnfs, --advisory ALAS2-2026-3367 (ALAS-2026-3367)	Nessus	Amazon Linux Local Security Checks	high
322054	Amazon Linux 2023 : libnfs, libnfs-devel, libnfs-utils (ALAS2023-2026-1855)	Nessus	Amazon Linux Local Security Checks	high
320496	Linux Distros Unpatched Vulnerability : CVE-2026-53689	Nessus	Misc.	high

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