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Fencer Vulns
medium 5.9

CVE-2020-16135 json

libssh 0.9.4 has a NULL pointer dereference in tftpserver.c if ssh_buffer_new returns NULL.

published 2020-07-29 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-8101

cvss
5.9
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
4.1%
EPSS 4.1% chance of exploitation in 30 days, percentile 90%
public exploits
0
none known

Summary

libssh 0.9.4 has a NULL pointer dereference in tftpserver.c if ssh_buffer_new returns NULL.

Patch / fix

  • libssh Debian 14, Debian 13, Debian 12 0.9.5-1

debian advisories DEBIAN-CVE-2020-16135

  • libssh Ubuntu 16.04 LTS 0.6.3-4.3ubuntu0.6
  • libssh Ubuntu 18.04 LTS 0.8.0~20170825.94fa1e38-1ubuntu0.7
  • libssh Ubuntu 20.04 LTS 0.9.3-2ubuntu2.1

ubuntu advisories UBUNTU-CVE-2020-16135

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • redhat-virtualization-host rhev hypervisor 4.4 4.4.9-202111172338_8.5
  • redhat-virtualization-host-image-update rhev hypervisor 4.4 4.4.9-202111172338_8.5
  • libssh RHEL 8 0.9.4-3.el8
  • libssh-config RHEL 8 0.9.4-3.el8

red hat advisories RHSA-2021:4750RHSA-2021:4387

  • libssh SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 0.9.8-3.12.2
  • libssh SLES for SAP 15 SP3, SLES for SAP 15 SP2, SLES 15 SP3-LTSS +6 more 0.9.8-150200.13.3.1

suse advisories SUSE-SU-2024:0539-1SUSE-SU-2024:0525-1

  • libssh openSUSE Tumbleweed 0.9.6-1.2

opensuse advisories openSUSE-SU-2024:10998-1

  • libssh Rocky Linux 8 0.9.4-3.el8

rocky linux advisories RLSA-2021:4387

  • libssh Alpine 3.10 0.8.9-r1
  • libssh Alpine 3.12, Alpine 3.11 0.9.4-r1
  • libssh Alpine 3.24, Alpine 3.23, Alpine 3.22 +9 more 0.9.5-r0
  • libssh Alpine 3.9 0.7.6-r3

alpine advisories ALPINE-CVE-2020-16135

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-16135 updated cvss 5.9

libssh: NULL pointer dereference in sftpserver.c if ssh_buffer_new returns NULL

  • Red Hat Enterprise Linux 7 libssh
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Enterprise Linux AppStream (v. 8) libssh-devel 0.9.4-3.el8, libssh-debuginfo 0.9.4-3.el8, libssh-debugsource 0.9.4-3.el8 Red Hat Enterprise Linux BaseOS (v. 8) libssh 0.9.4-3.el8, libssh-config 0.9.4-3.el8
    fixed: vendor fix RHSA-2021:4387
  • Red Hat Virtualization 4 Hypervisor for RHEL 8 redhat-virtualization-host 4.4.9-202111172338_8.5, redhat-virtualization-host-image-update 4.4.9-202111172338_8.5
    fixed: vendor fix RHSA-2021:4750
  • Red Hat Enterprise Linux 6 libssh2 Red Hat Enterprise Linux 7 libssh2 Red Hat Enterprise Linux 8 libssh2 Red Hat RHEL 8-based RHEV-H for RHEV 4 (build requirements) redhat-release-virtualization-host 4.4.9-2.el8ev, redhat-release-virtualization-host-content 4.4.9-2.el8ev, redhat-virtualization-host-image-update-placeholder 4.4.9-2.el8ev
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

4.11% chance of exploitation in the next 30 days, higher than 90% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • bugs.libssh.org https://bugs.libssh.org/rLIBSSHe631ebb3e2247dd25e9678e6827c20dc73b73238 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:N/A:P

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.