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Fencer Vulns
medium 5.5

CVE-2016-7796 json

The manager_dispatch_notify_fd function in systemd allows local users to cause a denial of service (system hang) via a zero-length message…

published 2016-10-13 10 y ago modified 2026-06-17 4 mo ago also EUVD-2016-8646

cvss
5.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 58%
public exploits
0
none known

Summary

The manager_dispatch_notify_fd function in systemd allows local users to cause a denial of service (system hang) via a zero-length message received over a notify socket, which causes an error to be returned and the notification handler to be disabled.

Patch / fix

  • systemd Debian 14, Debian 13, Debian 12 231-9

debian advisories DEBIAN-CVE-2016-7796

  • systemd Ubuntu 16.04 LTS 229-4ubuntu11

ubuntu advisories UBUNTU-CVE-2016-7796

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

  • systemd RHEL 7 219-19.el7
  • libgudev1 RHEL 7 219-19.el7
  • systemd-libs RHEL 7 219-19.el7
  • systemd-sysv RHEL 7 219-19.el7
  • systemd-python RHEL 7 219-19.el7
  • systemd-networkd RHEL 7 219-19.el7
  • systemd-resolved RHEL 7 219-19.el7
  • systemd-journal-gateway RHEL 7 219-19.el7

red hat advisories RHSA-2017:0003RHBA-2015:2092

  • systemd SLES for SAP 12 SP1, SLES 12 SP1, SLED 12 SP1 +1 more 210-114.1
  • systemd SLES for SAP 12, SLES 12-LTSS 210-70.58.1

suse advisories SUSE-SU-2016:2476-1SUSE-SU-2016:2475-1

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-2016-7796 updated cvss 6.8

systemd: freeze when PID 1 receives a zero-length message over notify socket

  • Red Hat Enterprise Linux Client (v. 7) systemd 219-19.el7, libgudev1 219-19.el7, systemd-libs 219-19.el7, systemd-sysv 219-19.el7, systemd-python 219-19.el7, systemd-networkd 219-19.el7, +2 more Red Hat Enterprise Linux Client Optional (v. 7) systemd 219-19.el7, libgudev1 219-19.el7, systemd-libs 219-19.el7, systemd-sysv 219-19.el7, systemd-python 219-19.el7, systemd-networkd 219-19.el7, +2 more Red Hat Enterprise Linux ComputeNode (v. 7) systemd 219-19.el7, libgudev1 219-19.el7, systemd-libs 219-19.el7, systemd-sysv 219-19.el7, systemd-python 219-19.el7, systemd-networkd 219-19.el7, +2 more
    fixed: vendor fix RHBA-2015:2092
  • Red Hat Enterprise Linux ComputeNode EUS (v. 7.1) systemd 208-20.el7_1.9, libgudev1 208-20.el7_1.9, systemd-libs 208-20.el7_1.9, systemd-sysv 208-20.el7_1.9, systemd-python 208-20.el7_1.9, systemd-journal-gateway 208-20.el7_1.9
    fixed: vendor fix RHSA-2017:0003
  • Red Hat Enterprise Linux ComputeNode Optional (v. 7) systemd 219-19.el7, libgudev1 219-19.el7, systemd-libs 219-19.el7, systemd-sysv 219-19.el7, systemd-python 219-19.el7, systemd-networkd 219-19.el7, +2 more
    fixed: vendor fix RHBA-2015:2092
  • Red Hat Enterprise Linux ComputeNode Optional EUS (v. 7.1) systemd 208-20.el7_1.9, libgudev1 208-20.el7_1.9, systemd-libs 208-20.el7_1.9, systemd-sysv 208-20.el7_1.9, systemd-python 208-20.el7_1.9, systemd-journal-gateway 208-20.el7_1.9
    fixed: vendor fix RHSA-2017:0003
  • Red Hat Enterprise Linux Server (v. 7) systemd 219-19.el7, libgudev1 219-19.el7, systemd-libs 219-19.el7, systemd-sysv 219-19.el7, systemd-python 219-19.el7, systemd-networkd 219-19.el7, +2 more
    fixed: vendor fix RHBA-2015:2092
  • Red Hat Enterprise Linux Server EUS (v. 7.1) systemd 208-20.el7_1.9, libgudev1 208-20.el7_1.9, systemd 208-20.ael7b_1.9, libgudev1 208-20.ael7b_1.9, systemd-libs 208-20.el7_1.9, systemd-sysv 208-20.el7_1.9, +6 more
    fixed: vendor fix RHSA-2017:0003
  • Red Hat Enterprise Linux Server Optional (v. 7) systemd 219-19.el7, libgudev1 219-19.el7, systemd-libs 219-19.el7, systemd-sysv 219-19.el7, systemd-python 219-19.el7, systemd-networkd 219-19.el7, +2 more
    fixed: vendor fix RHBA-2015:2092
  • Red Hat Enterprise Linux Server Optional EUS (v. 7.1) systemd 208-20.el7_1.9, libgudev1 208-20.el7_1.9, systemd 208-20.ael7b_1.9, libgudev1 208-20.ael7b_1.9, systemd-libs 208-20.el7_1.9, systemd-sysv 208-20.el7_1.9, +6 more
    fixed: vendor fix RHSA-2017:0003
show 1 more
  • Red Hat Enterprise Linux Workstation (v. 7) systemd 219-19.el7, libgudev1 219-19.el7, systemd-libs 219-19.el7, systemd-sysv 219-19.el7, systemd-python 219-19.el7, systemd-networkd 219-19.el7, +2 more Red Hat Enterprise Linux Workstation Optional (v. 7) systemd 219-19.el7, libgudev1 219-19.el7, systemd-libs 219-19.el7, systemd-sysv 219-19.el7, systemd-python 219-19.el7, systemd-networkd 219-19.el7, +2 more
    fixed: vendor fix RHBA-2015:2092

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

0.85% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/systemd/systemd/issues/4234#issuecomment-250441246 referenced PoC, tagged "exploit" by a source, unverified
  • agwa.name https://www.agwa.name/blog/post/how_to_crash_systemd_in_one_tweet referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 5.5 CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 4.9 AV:L/AC:L/Au:N/C:N/I:N/A:C

Classification

Weakness
  • CWE-20 Improper Input Validation

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.