A flaw was found in gnutls. A remote, unauthenticated attacker can exploit this vulnerability by sending a specially crafted ClientHello message with an invalid Pre-Shared Key (PSK) binder value during the TLS handshake. This can lead to a NULL pointer dereference, causing the server to crash and resulting in a remote Denial of Service (DoS) condition.

There are packages installed that are affected by multiple vulnerabilities referenced in the following CVEs:

  - A heap-buffer-overflow (off-by-one) flaw was found in the GnuTLS software in the template parsing logic
    within the certtool utility. When it reads certain settings from a template file, it allows an attacker to
    cause an out-of-bounds (OOB) NULL pointer write, resulting in memory corruption and a denial-of-service
    (DoS) that could potentially crash the system. (CVE-2025-32990)

  - A flaw was found in GnuTLS, which relies on libtasn1 for ASN.1 data processing. Due to an inefficient
    algorithm in libtasn1, decoding certain DER-encoded certificate data can take excessive time, leading to
    increased resource consumption. This flaw allows a remote attacker to send a specially crafted
    certificate, causing GnuTLS to become unresponsive or slow, resulting in a denial-of-service condition.
    (CVE-2024-12243)

  - A NULL pointer dereference flaw was found in the GnuTLS software in _gnutls_figure_common_ciphersuite().
    (CVE-2025-6395)

  - A flaw was found in the GnuTLS library, specifically in the gnutls_pkcs11_token_init() function that
    handles PKCS#11 token initialization. When a token label longer than expected is processed, the function
    writes past the end of a fixed-size stack buffer. This programming error can cause the application using
    GnuTLS to crash or, in certain conditions, be exploited for code execution. As a result, systems or
    applications relying on GnuTLS may be vulnerable to a denial of service or local privilege escalation
    attacks. (CVE-2025-9820)

  - A flaw was found in GnuTLS. This vulnerability allows a denial of service (DoS) by excessive CPU (Central
    Processing Unit) and memory consumption via specially crafted malicious certificates containing a large
    number of name constraints and subject alternative names (SANs). (CVE-2025-14831)

The version of gnutls installed on the remote host is prior to 3.8.12. It is, therefore, affected by multiple vulnerabilities as referenced in the SSA:2026-042-01 advisory.

    New gnutls packages are available for Slackware 15.0 and -current to fix security issues.

Tenable has extracted the preceding description block directly from the gnutls 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 42 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-2b6035ee2b advisory.

    This backports fixes for a couple CVEs:

    ** libgnutls: Fix NULL pointer dereference in PSK binder verification A TLS 1.3 resumption attempt with an     invalid PSK binder value in ClientHello could lead to a denial of service attack via crashing the server.
    The updated code guards against the problematic dereference. Reported by Jaehun Lee. [Fixes: GNUTLS-     SA-2026-02-09-1, CVSS: high] [CVE-2026-1584]

    ** libgnutls: Fix name constraint processing performance issue Verifying certificates with pathological     amounts of name constraints could lead to a denial of service attack via resource exhaustion. Reworked     processing algorithms exhibit better performance characteristics. Reported by Tim Scheckenbach. [Fixes:
    GNUTLS-SA-2026-02-09-2, CVSS: medium] [CVE-2025-14831]

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 Fedora 43 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-ef7170c9f6 advisory.

    This fixes a couple CVEs:

    ** libgnutls: Fix NULL pointer dereference in PSK binder verification A TLS 1.3 resumption attempt with an     invalid PSK binder value in ClientHello could lead to a denial of service attack via crashing the server.
    The updated code guards against the problematic dereference. Reported by Jaehun Lee. [Fixes: GNUTLS-     SA-2026-02-09-1, CVSS: high] [CVE-2026-1584]

    ** libgnutls: Fix name constraint processing performance issue Verifying certificates with pathological     amounts of name constraints could lead to a denial of service attack via resource exhaustion. Reworked     processing algorithms exhibit better performance characteristics. Reported by Tim Scheckenbach. [Fixes:
    GNUTLS-SA-2026-02-09-2, CVSS: medium] [CVE-2025-14831]

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

  - A flaw was found in gnutls. A remote, unauthenticated attacker can exploit this vulnerability by sending a     specially crafted ClientHello message with an invalid Pre-Shared Key (PSK) binder value during the TLS     handshake. This can lead to a NULL pointer dereference, causing the server to crash and resulting in a     remote Denial of Service (DoS) condition. (CVE-2026-1584)

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

ID	Name	Product	Family	Severity
437944	Alpine: multiple gnutls packages: security update to 3.8.12-r0	Tenable Cloud Security	Alpine Linux Local Security Checks	high
437944	Alpine: multiple gnutls packages: security update to 3.8.12-r0	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	high
299279	Slackware Linux 15.0 / current gnutls Multiple Vulnerabilities (SSA:2026-042-01)	Nessus	Slackware Local Security Checks	medium
299149	Fedora 42 : gnutls (2026-2b6035ee2b)	Nessus	Fedora Local Security Checks	medium
298695	Fedora 43 : gnutls (2026-ef7170c9f6)	Nessus	Fedora Local Security Checks	medium
298449	Linux Distros Unpatched Vulnerability : CVE-2026-1584	Nessus	Misc.	high

Detections

Analytics

CVE-2026-1584

high

Tenable Plugins

high

high

medium

medium

medium

high