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Libssh2Application

CVE-2026-58050

HIGH · 7.5 CVSS v3.1 Published 2026-06-28
Fix available
A fix is available. Upgrade to after 1.11.1 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click 7 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

libssh2 through 1.11.1 has a heap buffer overflow in its publickey-subsystem client handling. The library reads an attacker-controlled 32-bit attribute count from the server response and uses it in a multiplication for buffer allocation (num_attrs * sizeof(libssh2_publickey_attribute)) without any bounds checking. On 32-bit platforms, this multiplication can overflow to an undersized value, causing the subsequent attribute-parsing loop to write beyond the allocated buffer.

MitigationUpgrade libssh2 to the latest patched version. Until then, avoid connecting to untrusted or compromised SSH servers using libssh2-based clients, particularly on 32-bit platforms.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Libssh2Application
Affected:<= 1.11.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed libssh2 version
    Run 'pkg-config --modversion libssh2' or check the library file version (e.g., 'ldd' on the binary, or look for libssh2.so version in /usr/lib/)
    Affected if The version is 1.11.1 or lower
  2. Determine if publickey subsystem is used
    Inspect application code or runtime behavior for calls to libssh2 publickey functions such as libssh2_publickey_init, libssh2_publickey_list_parse, or similar publickey-related API calls
    Affected if The application or library invokes libssh2 publickey subsystem functions
  3. Check platform architecture
    Run 'uname -m' or 'getconf LONG_BIT' to determine if the system is 32-bit
    Affected if Running on a 32-bit platform (x86, ARM32)

A user is affected if their installed libssh2 version is 1.11.1 or lower AND the application uses the libssh2 publickey subsystem on a 32-bit platform.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 1.11.1
Interim mitigation

Upgrade libssh2 to the latest patched version. Until then, avoid connecting to untrusted or compromised SSH servers using libssh2-based clients, particularly on 32-bit platforms.

Recommended fix High confidence

libssh2 >= 1.11.2

  1. 1. Identify all systems, applications, or libraries that use libssh2 version 1.11.1 or earlier.
  2. 2. Locate the libssh2 library in your dependency tree (check package.json, requirements.txt, Cargo.toml, go.mod, or similar dependency files).
  3. 3. Upgrade libssh2 to version 1.11.2 or later. Use your package manager: pip install --upgrade libssh2, npm update libssh2, or your language's equivalent upgrade command.
  4. 4. Rebuild and recompile any applications that statically link libssh2.
  5. 5. Verify the upgrade was successful by checking the installed libssh2 version.
  6. 6. Test the SSH client functionality to ensure the upgrade does not break existing functionality.

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Libssh2 Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
16.0 hours of engineering $2,760
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-58050 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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