CVE-2019-3862

CVE-2019-3862 is a high-severity vulnerability in Libssh2 with a CVSS 3.x base score of 7.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.

Key facts

• Severity: High (CVSS 3.x base score 7.3)
• CVSS v2: 6.4
• EPSS exploit prediction: 8% (94th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-125
• Affected product: Libssh2
• Published: 2019-03-21
• Last modified: 2026-06-17

Description

An out of bounds read flaw was discovered in libssh2 before 1.8.1 in the way SSH_MSG_CHANNEL_REQUEST packets with an exit status message and no payload are parsed. A remote attacker who compromises a SSH server may be able to cause a Denial of Service or read data in the client memory.

Frequently asked questions

What is CVE-2019-3862?

An out of bounds read flaw was discovered in libssh2 before 1.8.1 in the way SSH_MSG_CHANNEL_REQUEST packets with an exit status message and no payload are parsed. A remote attacker who compromises a SSH server may be able to cause a Denial of Service or read data in the client memory.

How severe is CVE-2019-3862?

CVE-2019-3862 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2019-3862 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 8% (94th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-3862?

CVE-2019-3862 primarily affects Libssh2. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-3862?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2019-3862 published?

CVE-2019-3862 was published on 2019-03-21 and last updated on 2026-06-17.

References

• http://lists.opensuse.org/opensuse-security-announce/2019-03/msg00040.html
• http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00003.html
• http://packetstormsecurity.com/files/152136/Slackware-Security-Advisory-libssh2-Updates.html
• http://www.openwall.com/lists/oss-security/2019/03/18/3
• http://www.securityfocus.com/bid/107485
• https://access.redhat.com/errata/RHSA-2019:1884
• https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-3862
• https://lists.debian.org/debian-lts-announce/2019/03/msg00032.html
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5DK6VO2CEUTAJFYIKWNZKEKYMYR3NO2O/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XCWEA5ZCLKRDUK62QVVYMFWLWKOPX3LO/
• https://seclists.org/bugtraq/2019/Apr/25
• https://seclists.org/bugtraq/2019/Mar/25
• https://security.netapp.com/advisory/ntap-20190327-0005/
• https://www.broadcom.com/support/fibre-channel-networking/security-advisories/brocade-security-advisory-2019-767
• https://www.debian.org/security/2019/dsa-4431
• https://www.libssh2.org/CVE-2019-3862.html
• https://www.oracle.com/security-alerts/cpujan2020.html
• https://www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.html

Affected products (5)

• cpe:2.3:a:libssh2:libssh2:*:*:*:*:*:*:*:*
• cpe:2.3:o:fedoraproject:fedora:29:*:*:*:*:*:*:*
• cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
• cpe:2.3:a:netapp:ontap_select_deploy_administration_utility:-:*:*:*:*:*:*:*
• cpe:2.3:o:opensuse:leap:42.3:*:*:*:*:*:*:*

More vulnerabilities in Libssh2

• CVE-2019-3859 — Critical (CVSS 9.1): An out of bounds read flaw was discovered in libssh2 before 1.8.1 in the _libssh2_packet_require and…
• CVE-2019-3857 — High (CVSS 8.8): An integer overflow flaw which could lead to an out of bounds write was discovered in libssh2 before 1.8.1 in the way…
• CVE-2019-3856 — High (CVSS 8.8): An integer overflow flaw, which could lead to an out of bounds write, was discovered in libssh2 before 1.8.1 in the way…
• CVE-2019-3855 — High (CVSS 8.8): An integer overflow flaw which could lead to an out of bounds write was discovered in libssh2 before 1.8.1 in the way…
• CVE-2026-55200 — High (CVSS 8.1): libssh2 through 1.11.1, fixed in commit 7acf3df contains an out-of-bounds write vulnerability in ssh2_transport_read()…
• CVE-2019-17498 — High (CVSS 8.1): In libssh2 v1.9.0 and earlier versions, the SSH_MSG_DISCONNECT logic in packet.c has an integer overflow in a bounds…

All CVEs affecting Libssh2 →

Other CWE-125 (Out-of-bounds Read) vulnerabilities

• CVE-2026-24826 — Critical (CVSS 10.0): Out-of-bounds Write, Divide By Zero, NULL Pointer Dereference, Use of Uninitialized Resource, Out-of-bounds Read,…
• CVE-2024-22004 — Critical (CVSS 10.0): Due to length check, an attacker with privilege access on a Linux Nonsecure operating system can trigger a…
• CVE-2021-41556 — Critical (CVSS 10.0): sqclass.cpp in Squirrel through 2.2.5 and 3.x through 3.1 allows an out-of-bounds read (in the core interpreter) that…
• CVE-2021-21777 — Critical (CVSS 10.0): An information disclosure vulnerability exists in the Ethernet/IP UDP handler functionality of EIP Stack Group OpENer…
• CVE-2017-14451 — Critical (CVSS 10.0): An exploitable out-of-bounds read vulnerability exists in libevm (Ethereum Virtual Machine) of CPP-Ethereum. A…
• CVE-2013-0767 — Critical (CVSS 10.0): The nsSVGPathElement::GetPathLengthScale function in Mozilla Firefox before 18.0, Firefox ESR 10.x before 10.0.12 and…

Browse all CWE-125 (Out-of-bounds Read) vulnerabilities →