Mbed TLS before 3.6.4 has a PEM parsing one-byte heap-based buffer underflow, in mbedtls_pem_read_buffer and two mbedtls_pk_parse functions, via untrusted PEM input.

The remote Fedora 44 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-52a9a687f0 advisory.

    Update to 1.28.0

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-2026-29f4f47ade advisory.

    Update to 1.28.0

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 45 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-d619d8d077 advisory.

    Automatic update for micropython-1.28.0-1.fc45.

    ##### **Changelog**

    ```
    * Mon Apr  6 2026 Lumr Balhar <lbalhar@redhat.com> - 1.28.0-1
    - Update to 1.28.0
    - Security fix for CVE-2026-1998
    - Update mbedtls submodule to 3.6.6
    - mbedtls security fixes for CVE-2026-25834, CVE-2026-34871, CVE-2026-25833
    - CVE-2025-52496, CVE-2025-52497, CVE-2025-49087, CVE-2025-54764, CVE-2025-59438      Resolves: rhbz#2455368, rhbz#2376688, rhbz#2376701, rhbz#2382261, rhbz#2405245,      rhbz#2405374, rhbz#2437327, rhbz#2454032, rhbz#2454086, rhbz#2454213

    ```

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 Ubuntu 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8123-1 advisory.

    It was discovered that Mbed TLS incorrectly handled memory allocation failures. A remote attacker could     possibly use this issue to crash the program. This issue only affected Ubuntu 18.04 LTS and Ubuntu 20.04     LTS. (CVE-2021-44732)

    Jonathan Winzig discovered that Mbed TLS incorrectly handled crafted inputs. A remote attacker could     possibly use this issue to crash the program, resulting in a denial of service. This issue only affected     Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS. (CVE-2024-23775)

    It was discovered that Mbed TLS incorrectly handled the TLS handshake. A remote attacker could possibly     use this issue to break the security guarantees of the TLS handshake. (CVE-2025-27810)

    Linh Le and Ngan Nguyen discovered that Mbed TLS incorrectly documented the behavior of a function.
    Application code relying on the documented behavior might be affected. A remote attacker could possibly     use this issue to execute arbitrary code. (CVE-2025-47917)

    Linh Le and Ngan Nguyen discovered that Mbed TLS incorrectly handled crafted input. A remote attacker     could possibly use this issue to crash the program, resulting in a denial of service. (CVE-2025-48965)

    It was discovered that Mbed TLS incorrectly handled a race condition. An attacker could possibly use this     issue to extract AES keys. (CVE-2025-52496)

    Linh Le and Ngan Nguyen discovered that Mbed TLS incorrectly handled certain invalid input. A remote     attacker could possibly use this issue to crash the program, resulting in a denial of service.
    (CVE-2025-52497)

Tenable has extracted the preceding description block directly from the Ubuntu 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 version of Tencent Linux installed on the remote TencentOS Server 4 host is prior to tested version. It is, therefore, affected by multiple vulnerabilities as referenced in the TSSA-2025:0533 advisory.

    Package updates are available for TencentOS Server 4 that fix the following vulnerabilities:

    CVE-2025-52497:
    Mbed TLS before 3.6.4 has a PEM parsing one-byte heap-based buffer underflow, in mbedtls_pem_read_buffer     and two mbedtls_pk_parse functions, via untrusted PEM input.

    CVE-2025-52496:
    Mbed TLS before 3.6.4 has a race condition in AESNI detection if certain compiler optimizations occur. An     attacker may be able to extract an AES key from a multithreaded program, or perform a GCM forgery.

Tenable has extracted the preceding description block directly from the Tencent 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 Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - Mbed TLS before 3.6.4 has a PEM parsing one-byte heap-based buffer underflow, in mbedtls_pem_read_buffer     and two mbedtls_pk_parse functions, via untrusted PEM input. (CVE-2025-52497)

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

ID	Name	Product	Family	Severity
310204	Fedora 44 : micropython (2026-52a9a687f0)	Nessus	Fedora Local Security Checks	medium
306614	Fedora 43 : micropython (2026-29f4f47ade)	Nessus	Fedora Local Security Checks	medium
306036	Fedora 45 : micropython (2026-d619d8d077)	Nessus	Fedora Local Security Checks	medium
304014	Ubuntu 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS : Mbed TLS vulnerabilities (USN-8123-1)	Nessus	Ubuntu Local Security Checks	critical
276316	TencentOS Server 4: mbedtls (TSSA-2025:0533)	Nessus	Tencent Local Security Checks	high
245660	Linux Distros Unpatched Vulnerability : CVE-2025-52497	Nessus	Misc.	medium

Detections

Analytics

CVE-2025-52497

medium

Tenable Plugins

medium

medium

medium

critical

high

medium