OESA-2026-3394 (CVE-2026-58050)

Vulnerability from osv_openeuler – Published: 2026-08-13 14:02 – Updated: 2026-08-13 14:02 – Source website
VLAI
Summary
libssh2 security update
Details

libssh2 is a library implementing the SSH2 protocol as defined by Internet Drafts: SECSH-TRANS(22), SECSH-USERAUTH(25), SECSH-CONNECTION(23), SECSH-ARCH(20), SECSH-FILEXFER(06)*, SECSH-DHGEX(04), and SECSH-NUMBERS(10).

Security Fix(es):

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, fixed in commit 5e47761, contains a double-free vulnerability in the sftp_open() function in src/sftp.c that allows a malicious SSH server to corrupt the heap of any authenticated client opening an SFTP session. When a server responds to SSH_FXP_OPEN with SSH_FXP_STATUS containing FX_OK, the response data buffer is freed, and if a subsequent sftp_packet_require() call returns a specific error such as LIBSSH2_ERROR_CHANNEL_PACKET_EXCEEDED, the same pointer is freed a second time, enabling tcache dup conditions on glibc systems that allow overlapping allocations and function pointer overwrites.(CVE-2026-66032)

libssh2 through 1.11.1, fixed in commit a13bb6c, contains a missing bounds check vulnerability that allows a malicious SSH server to trigger an arbitrary-length heap out-of-bounds read and a free of an uninitialized pointer via the publickey subsystem. In libssh2_publickey_list_fetch(), the version 1 response parser reads a server-controlled comment_len value and advances the parse pointer without verifying sufficient bytes remain in the buffer, causing the out-of-bounds read to leak heap pointers from adjacent allocations defeating ASLR, followed by heap allocator state corruption when the error cleanup path frees an uninitialized pointer from a non-zeroed realloc() region.(CVE-2026-66034)

Severity
8.8 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "aarch64": [
          "libssh2-1.10.0-13.oe2203sp4.aarch64.rpm",
          "libssh2-debuginfo-1.10.0-13.oe2203sp4.aarch64.rpm",
          "libssh2-debugsource-1.10.0-13.oe2203sp4.aarch64.rpm",
          "libssh2-devel-1.10.0-13.oe2203sp4.aarch64.rpm"
        ],
        "noarch": [
          "libssh2-help-1.10.0-13.oe2203sp4.noarch.rpm"
        ],
        "src": [
          "libssh2-1.10.0-13.oe2203sp4.src.rpm"
        ],
        "x86_64": [
          "libssh2-1.10.0-13.oe2203sp4.x86_64.rpm",
          "libssh2-debuginfo-1.10.0-13.oe2203sp4.x86_64.rpm",
          "libssh2-debugsource-1.10.0-13.oe2203sp4.x86_64.rpm",
          "libssh2-devel-1.10.0-13.oe2203sp4.x86_64.rpm"
        ]
      },
      "package": {
        "ecosystem": "openEuler:22.03-LTS-SP4",
        "name": "libssh2",
        "purl": "pkg:rpm/openEuler/libssh2\u0026distro=openEuler-22.03-LTS-SP4"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.10.0-13.oe2203sp4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "severity": "High"
  },
  "details": "libssh2 is a library implementing the SSH2 protocol as defined by Internet Drafts: SECSH-TRANS(22), SECSH-USERAUTH(25), SECSH-CONNECTION(23), SECSH-ARCH(20), SECSH-FILEXFER(06)*, SECSH-DHGEX(04), and SECSH-NUMBERS(10).\r\n\r\nSecurity Fix(es):\n\nlibssh2 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)\n\nlibssh2 through 1.11.1, fixed in commit 5e47761, contains a double-free vulnerability in the sftp_open() function in src/sftp.c that allows a malicious SSH server to corrupt the heap of any authenticated client opening an SFTP session. When a server responds to SSH_FXP_OPEN with SSH_FXP_STATUS containing FX_OK, the response data buffer is freed, and if a subsequent sftp_packet_require() call returns a specific error such as LIBSSH2_ERROR_CHANNEL_PACKET_EXCEEDED, the same pointer is freed a second time, enabling tcache dup conditions on glibc systems that allow overlapping allocations and function pointer overwrites.(CVE-2026-66032)\n\nlibssh2 through 1.11.1, fixed in commit a13bb6c, contains a missing bounds check vulnerability that allows a malicious SSH server to trigger an arbitrary-length heap out-of-bounds read and a free of an uninitialized pointer via the publickey subsystem. In libssh2_publickey_list_fetch(), the version 1 response parser reads a server-controlled comment_len value and advances the parse pointer without verifying sufficient bytes remain in the buffer, causing the out-of-bounds read to leak heap pointers from adjacent allocations defeating ASLR, followed by heap allocator state corruption when the error cleanup path frees an uninitialized pointer from a non-zeroed realloc() region.(CVE-2026-66034)",
  "id": "OESA-2026-3394",
  "modified": "2026-08-13T14:02:39Z",
  "published": "2026-08-13T14:02:39Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-3394"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-58050"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-66032"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-66034"
    }
  ],
  "schema_version": "1.7.2",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "libssh2 security update",
  "upstream": [
    "CVE-2026-58050",
    "CVE-2026-66032",
    "CVE-2026-66034"
  ]
}



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