Security readout for executives and security teams
CVE-2019-3859 is a critical libssh2 client-side memory read flaw. If a client using vulnerable libssh2 connects to a compromised or malicious SSH server, the server may crash the client or read client memory. This matters for automation, file transfer, backup, deployment, and embedded products that rely on libssh2. Exposure is likely where systems embed or package libssh2 for outbound SSH, SCP, or SFTP client connections. The most relevant risk is clients connecting to untrusted, compromised, or attacker-controlled SSH servers. Inventory both operating system packages and bundled application dependencies. High priority for environments using libssh2-based clients against external SSH services. The issue is old but severe, and many products bundle libraries. Confirm patch status through asset inventory and vendor advisories before assuming operating system updates covered every instance. Mitigation focus: Upgrade libssh2 to 1.8.1 or a vendor-supported fixed package.; Apply distribution updates from Debian, Fedora, Slackware, openSUSE, or relevant vendors.; Rebuild and redeploy applications that bundle libssh2 statically..
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
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CWE-125: Exact CWE lookup
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Open ATT&CK lookupCVE-2019-3859 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H3.95.2Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.1CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20190319 [slackware-security] libssh2 (SSA:2019-077-01)CVE reference · mailing-list, x_refsource_BUGTRAQ
- https://www.libssh2.org/CVE-2019-3859.htmlCVE reference · x_refsource_MISC
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-3859CVE reference · x_refsource_CONFIRM
- FEDORA-2019-f31c14682fCVE reference · vendor-advisory, x_refsource_FEDORA
- https://www.broadcom.com/support/fibre-channel-networking/security-advisories/brocade-security-advisory-2019-767CVE reference · x_refsource_CONFIRM
- [debian-lts-announce] 20190326 [SECURITY] [DLA 1730-1] libssh2 security updateCVE reference · mailing-list, x_refsource_MLIST
- https://security.netapp.com/advisory/ntap-20190327-0005/CVE reference · x_refsource_CONFIRM
- [debian-lts-announce] 20190402 [SECURITY] [DLA 1730-2] libssh2 regression updateCVE reference · mailing-list, x_refsource_MLIST
- FEDORA-2019-3348cb4934CVE reference · vendor-advisory, x_refsource_FEDORA
- DSA-4431CVE reference · vendor-advisory, x_refsource_DEBIAN
- 20190415 [SECURITY] [DSA 4431-1] libssh2 security updateCVE reference · mailing-list, x_refsource_BUGTRAQ
- [debian-lts-announce] 20190725 [SECURITY] [DLA 1730-3] libssh2 regression updateCVE reference · mailing-list, x_refsource_MLIST
- https://www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.htmlCVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Out-of-bounds Read
Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.