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CVE-2019-3858· NVD / CVE Program· CNA redhat

An out of bounds read flaw was discovered in libssh2 before 1.8.1 when a specially crafted SFTP packet is received from the server.

Noroxi assessment

Priority: Monitor (action score 38/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 6.4% (FIRST EPSS); higher than 93.5% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: libssh2 (Alpine:v3.10) 1.8.1-r0; libssh2 (Debian:12) 1.8.0-2.1; libssh2 (Debian:8) 1.4.3-4.1+deb8u2.
  • Severity is disputed: the assigning authority (CNA) scores it 5.0, NVD 9.1.

Low priority for now. Upgrade to libssh2 (Alpine:v3.10) 1.8.1-r0; libssh2 (Debian:12) 1.8.0-2.1; libssh2 (Debian:8) 1.4.3-4.1+deb8u2 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

An out of bounds read flaw was discovered in libssh2 before 1.8.1 when a specially crafted SFTP packet is received from the server. A remote attacker who compromises a SSH server may be able to cause a Denial of Service or read data in the client memory.

CriticalCVSS 9.1 · v3.0—No exploit Fix available
Published
Mar 21, 2019
Updated
Jun 16, 2026
EPSS
6.4% · 94th percentile

Report tools

JSON

Action score

38

Monitor

Low priority for now.

CVSS
36 / 40 · 9.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
2 / 30 · 6.4%

CNA vs NVD score

NVD
9.1
CNA · redhat
5.0
4.1 point gap

CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2019-3858

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
libssh2libssh2
fedoraprojectfedora
debiandebian linux
netappontap select deploy administration utility
opensuseleap

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • debian debian linux8.0
  • fedoraproject fedora29
  • libssh2 libssh2before 1.8.1
  • netapp ontap select deploy administration utilityall versions
  • opensuse leap15.0
  • opensuse leap42.3

Versions reported by the vendor

Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.

  • The libssh2 Project libssh2

    • 1.8.1affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.10libssh2before 1.8.1-r01.8.1-r0
Debian:12libssh2before 1.8.0-2.11.8.0-2.1
Debian:8libssh2before 1.4.3-4.1+deb8u21.4.3-4.1+deb8u2
Debian:9libssh2before 1.7.0-1+deb9u11.7.0-1+deb9u1
openSUSE:Leap 15.0libssh2_orgbefore 1.8.0-lp150.3.3.11.8.0-lp150.3.3.1
openSUSE:Leap 15.1libssh2_orgbefore 1.9.0-lp151.6.6.11.9.0-lp151.6.6.1
openSUSE:Leap 15.2libssh2_orgbefore 1.9.0-lp152.8.3.11.9.0-lp152.8.3.1
openSUSE:Tumbleweedlibssh2_orgbefore 1.9.0-3.61.9.0-3.6
Red Hat:enterprise_linux:7::clientlibssh2before 0:1.8.0-3.el70:1.8.0-3.el7
Red Hat:enterprise_linux:7::clientlibssh2-debuginfobefore 0:1.8.0-3.el70:1.8.0-3.el7
Red Hat:enterprise_linux:7::clientlibssh2-develbefore 0:1.8.0-3.el70:1.8.0-3.el7
Red Hat:enterprise_linux:7::clientlibssh2-docsbefore 0:1.8.0-3.el70:1.8.0-3.el7
SUSE:Linux Enterprise Module for Basesystem 15 SP1libssh2_orgbefore 1.9.0-4.13.11.9.0-4.13.1
SUSE:Linux Enterprise Point of Sale 11 SP3libssh2_orgbefore 1.2.9-4.2.12.5.11.2.9-4.2.12.5.1
SUSE:Linux Enterprise Software Development Kit 11 SP4libssh2_orgbefore 1.4.3-17.3.11.4.3-17.3.1
SUSE:OpenStack Cloud 7libssh2_orgbefore 1.4.3-20.3.11.4.3-20.3.1

Same product

libssh2: all records

Other highest-scoring records for the same primary product.

  • CVE-2019-3861An out of bounds read flaw was discovered in libssh2 before 1.8.1 in the way SSH packets with a padding length value greater than the packet
    38Monitor
  • CVE-2019-3860An out of bounds read flaw was discovered in libssh2 before 1.8.1 in the way SFTP packets with empty payloads are parsed.
    38Monitor
  • CVE-2019-3855An integer overflow flaw which could lead to an out of bounds write was discovered in libssh2 before 1.8.1 in the way packets are read from
    38Monitor
  • CVE-2019-3862An 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
    38Monitor
  • CVE-2019-3859An out of bounds read flaw was discovered in libssh2 before 1.8.1 in the _libssh2_packet_require and _libssh2_packet_requirev functions.
    38Monitor
  • CVE-2019-3857An integer overflow flaw which could lead to an out of bounds write was discovered in libssh2 before 1.8.1 in the way SSH_MSG_CHANNEL_REQUES
    37Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
alpine:libssh21.8.1-r0 · Alpine:v3.10Package registry (OSV)
debian:libssh21.8.0-2.1 · Debian:12Package registry (OSV)
opensuse:libssh2_org1.8.0-lp150.3.3.1 · openSUSE:Leap 15.0Package registry (OSV)
red hat:libssh20:1.8.0-3.el7 · Red Hat:enterprise_linux:7::clientPackage registry (OSV)
red hat:libssh2-debuginfo0:1.8.0-3.el7 · Red Hat:enterprise_linux:7::clientPackage registry (OSV)
red hat:libssh2-devel0:1.8.0-3.el7 · Red Hat:enterprise_linux:7::clientPackage registry (OSV)
red hat:libssh2-docs0:1.8.0-3.el7 · Red Hat:enterprise_linux:7::clientPackage registry (OSV)
suse:libssh2_org1.4.3-20.3.1 · SUSE:OpenStack Cloud 7Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-125 · Out-of-bounds Read

CVSS vector

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (16 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records