libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-subsystem response and uses it in the allocation num_attrs * sizeof(libssh2_publickey_attribute) without bounds checking, so on 32-bit platforms the multiplication overflows to an undersized buffer. A malicious SSH server can then drive the attribute-parsing loop to write past the allocation, causing a heap buffer overflow in a connecting libssh2 client.

The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2026-102700 advisory.

    libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-subsystem     response and uses it in the allocation num_attrs * sizeof(libssh2_publickey_attribute) without bounds     checking, so on 32-bit platforms the multiplication overflows to an undersized buffer. A malicious SSH     server can then drive the attribute-parsing loop to write past the allocation, causing a heap buffer     overflow in a connecting libssh2 client.

Tenable has extracted the preceding description block directly from the Unity Linux 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 multiple vulnerabilities as referenced in the openSUSE-SU-2026:21549-1 advisory.

    - CVE-2025-15661: out-of-bounds heap read vulnerability in the `sftp_symlink()` function in `src/sftp.c`     (bsc#1268546).
    - CVE-2026-7598: integer overflow in function `userauth_password` of file `src/userauth.c` (bsc#1263890).
    - CVE-2026-58050: heap buffer overflow due to missing bounds check in attribute count of publickey-     subsystem response       (bsc#1269568).
    - CVE-2026-58051: uninitialized pointer freed when malformed responses are sent by an SSH server     (bsc#1269567).
    - CVE-2026-66032: arbitrary code execution via double-free in SFTP session (bsc#1272737).
    - CVE-2026-66033: denial of service via integer underflow in AES-GCM cipher negotiation (bsc#1272736).
    - CVE-2026-66034: information disclosure and potential arbitrary code execution via heap out-of-bounds     read       (bsc#1272735).
    - CVE-2026-66035: arbitrary code execution via heap buffer overflow during SSH negotiation (bsc#1272734).

Tenable has extracted the preceding description block directly from the SUSE 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 SUSE Linux SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:3541-1 advisory.

    - CVE-2025-15661: out-of-bounds heap read vulnerability in the `sftp_symlink()` function in `src/sftp.c`     (bsc#1268546).
    - CVE-2026-7598: integer overflow in function `userauth_password` of file `src/userauth.c` (bsc#1263890).
    - CVE-2026-58050: heap buffer overflow due to missing bounds check in attribute count of publickey-     subsystem response       (bsc#1269568).
    - CVE-2026-58051: uninitialized pointer freed when malformed responses are sent by an SSH server     (bsc#1269567).
    - CVE-2026-66032: arbitrary code execution via double-free in SFTP session (bsc#1272737).
    - CVE-2026-66033: denial of service via integer underflow in AES-GCM cipher negotiation (bsc#1272736).
    - CVE-2026-66034: information disclosure and potential arbitrary code execution via heap out-of-bounds     read       (bsc#1272735).
    - CVE-2026-66035: arbitrary code execution via heap buffer overflow during SSH negotiation (bsc#1272734).

Tenable has extracted the preceding description block directly from the SUSE 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 SUSE Linux SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:3526-1 advisory.

    - CVE-2025-15661: out-of-bounds heap read vulnerability in the `sftp_symlink()` function in `src/sftp.c`     (bsc#1268546).
    - CVE-2026-7598: integer overflow in function `userauth_password` of file `src/userauth.c` (bsc#1263890).
    - CVE-2026-58050: heap buffer overflow due to missing bounds check in attribute count of publickey-     subsystem response       (bsc#1269568).
    - CVE-2026-58051: uninitialized pointer freed when malformed responses are sent by an SSH server     (bsc#1269567).
    - CVE-2026-66032: arbitrary code execution via double-free in SFTP session (bsc#1272737).
    - CVE-2026-66033: denial of service via integer underflow in AES-GCM cipher negotiation (bsc#1272736).
    - CVE-2026-66034: information disclosure and potential arbitrary code execution via heap out-of-bounds     read       (bsc#1272735).
    - CVE-2026-66035: arbitrary code execution via heap buffer overflow during SSH negotiation (bsc#1272734).

Tenable has extracted the preceding description block directly from the SUSE 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 SUSE Linux SLES12 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:3525-1 advisory.

    - CVE-2025-15661: out-of-bounds heap read vulnerability in the `sftp_symlink()` function in `src/sftp.c`     (bsc#1268546).
    - CVE-2026-7598: integer overflow in function `userauth_password` of file `src/userauth.c` (bsc#1263890).
    - CVE-2026-55199: pre-authentication DoS via the `SSH_MSG_EXT_INFO` handler (bsc#1268530).
    - CVE-2026-58050: heap buffer overflow due to missing bounds check in attribute count of publickey-     subsystem response       (bsc#1269568).
    - CVE-2026-58051: uninitialized pointer freed when malformed responses are sent by an SSH server     (bsc#1269567).
    - CVE-2026-66032: arbitrary code execution via double-free in SFTP session (bsc#1272737).
    - CVE-2026-66033: denial of service via integer underflow in AES-GCM cipher negotiation (bsc#1272736).
    - CVE-2026-66034: information disclosure and potential arbitrary code execution via heap out-of-bounds     read       (bsc#1272735).
    - CVE-2026-66035: arbitrary code execution via heap buffer overflow during SSH negotiation (bsc#1272734).

Tenable has extracted the preceding description block directly from the SUSE 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 libssh2 installed on the remote host is prior to 1.4.3-12. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2026-3813 advisory.

    libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-subsystem     response and uses it in the allocation num_attrs * sizeof(libssh2_publickey_attribute) without bounds     checking, so on 32-bit platforms the multiplication overflows to an undersized buffer. A malicious SSH     server can then drive the attribute-parsing loop to write past the allocation, causing a heap buffer     overflow in a connecting libssh2 client. (CVE-2026-58050)

    libssh2 through 1.11.1 grows its publickey list with SSH2_REALLOC but does not zero-initialize new entries     before parsing populates them, so a parse failure reaching the cleanup path leaves     libssh2_publickey_list_free operating on an uninitialized entry. A malicious SSH server offering the     publickey subsystem can use a malformed response to make cleanup free an uninitialized, attacker-     influenceable attrs pointer in a connecting libssh2 client. (CVE-2026-58051)

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

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

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-1966 advisory.

    libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-subsystem     response and uses it in the allocation num_attrs * sizeof(libssh2_publickey_attribute) without bounds     checking, so on 32-bit platforms the multiplication overflows to an undersized buffer. A malicious SSH     server can then drive the attribute-parsing loop to write past the allocation, causing a heap buffer     overflow in a connecting libssh2 client. (CVE-2026-58050)

    libssh2 through 1.11.1 grows its publickey list with SSH2_REALLOC but does not zero-initialize new entries     before parsing populates them, so a parse failure reaching the cleanup path leaves     libssh2_publickey_list_free operating on an uninitialized entry. A malicious SSH server offering the     publickey subsystem can use a malformed response to make cleanup free an uninitialized, attacker-     influenceable attrs pointer in a connecting libssh2 client. (CVE-2026-58051)

Tenable has extracted the preceding description block directly from the tested product 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 24.04 LTS / 26.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8532-1 advisory.

    It was discovered that libssh2 incorrectly handled certain publickey subsystem attributes. A remote     attacker controlling a malicious SSH server could use this issue to cause a denial of service or possibly     execute arbitrary code. (CVE-2026-58050)

    It was discovered that libssh2 did not properly initialize publickey list entries before parsing. A remote     attacker controlling a malicious SSH server could use this issue to cause a denial of service or possibly     execute arbitrary code. (CVE-2026-58051)

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-2026:0572 advisory.

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

    CVE-2026-58051:
    libssh2 through 1.11.1 grows its publickey list with SSH2_REALLOC but does not zero-initialize new entries     before parsing populates them, so a parse failure reaching the cleanup path leaves     libssh2_publickey_list_free operating on an uninitialized entry. A malicious SSH server offering the     publickey subsystem can use a malformed response to make cleanup free an uninitialized, attacker-     influenceable attrs pointer in a connecting libssh2 client.

    CVE-2026-58050:
    libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-subsystem     response and uses it in the allocation num_attrs * sizeof(libssh2_publickey_attribute) without bounds     checking, so on 32-bit platforms the multiplication overflows to an undersized buffer. A malicious SSH     server can then drive the attribute-parsing loop to write past the allocation, causing a heap buffer     overflow in a connecting libssh2 client.

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.

  - libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-subsystem     response and uses it in the allocation num_attrs * sizeof(libssh2_publickey_attribute) without bounds     checking, so on 32-bit platforms the multiplication overflows to an undersized buffer. A malicious SSH     server can then drive the attribute-parsing loop to write past the allocation, causing a heap buffer     overflow in a connecting libssh2 client. (CVE-2026-58050)

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

ID	Name	Product	Family	Type	Severity
338487	Unity Linux 20.1050e / 20.1060e / 20.1070e Security Update: libssh2 (UTSA-2026-102700)	Nessus	Unity Linux Local Security Checks	Local	high
335046	openSUSE 16 Security Update : libssh2_org (openSUSE-SU-2026:21549-1)	Nessus	SuSE Local Security Checks	Local	high
334785	SUSE SLED15 / SLES15 Security Update : libssh2_org (SUSE-SU-2026:3541-1)	Nessus	SuSE Local Security Checks	Local	high
333544	SUSE SLES15 Security Update : libssh2_org (SUSE-SU-2026:3526-1)	Nessus	SuSE Local Security Checks	Local	high
333542	SUSE SLES12 Security Update : libssh2_org (SUSE-SU-2026:3525-1)	Nessus	SuSE Local Security Checks	Local	high
328836	Amazon Linux 2 : libssh2, --advisory ALAS2-2026-3813 (ALAS-2026-3813)	Nessus	Amazon Linux Local Security Checks	Local	high
328482	Amazon Linux 2023 : libssh2, libssh2-devel (ALAS2023-2026-1966)	Nessus	Amazon Linux Local Security Checks	Local	high
326802	Ubuntu 24.04 LTS / 26.04 LTS : libssh2 vulnerabilities (USN-8532-1)	Nessus	Ubuntu Local Security Checks	Local	high
325859	TencentOS Server 4: libssh2 (TSSA-2026:0572)	Nessus	Tencent Local Security Checks	Local	high
323517	Linux Distros Unpatched Vulnerability : CVE-2026-58050	Nessus	Misc.	Local	high

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CVE-2026-58050

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