The send_dg function in resolv/res_send.c in GNU C Library (aka glibc or libc6) before 2.20 does not properly reuse file descriptors, which…

published 2015-02-24 11y ago modified 2026-06-17 4mo ago also EUVD-2013-7187

cvss: 5.0; version 2.0, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 5.8%; EPSS 5.8% chance of exploitation in 30 days, percentile 93%
public exploits: 0; none known

The send_dg function in resolv/res_send.c in GNU C Library (aka glibc or libc6) before 2.20 does not properly reuse file descriptors, which allows remote attackers to send DNS queries to unintended locations via a large number of requests that trigger a call to the getaddrinfo function.

Patch / fix

fixed in 1 distros 5

gnu glibc 2.20

debian ubuntu red hat suse opensuse

glibc Debian 14, Debian 13, Debian 12 2.19-1

debian advisories DEBIAN-CVE-2013-7423

eglibc Ubuntu 14.04 LTS 2.19-0ubuntu6.6

ubuntu advisories UBUNTU-CVE-2013-7423

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

glibc RHEL 7 2.17-105.el7
nscd RHEL 7 2.17-105.el7
glibc-utils RHEL 7 2.17-105.el7
glibc-common RHEL 7 2.17-105.el7
glibc-debuginfo-common RHEL 7 2.17-105.el7
glibc RHEL 6 2.12-1.149.el6_6.7
nscd RHEL 6 2.12-1.149.el6_6.7
glibc-utils RHEL 6 2.12-1.149.el6_6.7

red hat advisories RHSA-2015:2589 RHSA-2015:2199 RHSA-2016:1207 RHSA-2015:0863

glibc SLES for SAP 12, SLES 12, SLED 12 +1 more 2.19-20.3

suse advisories SUSE-SU-2015:0526-1

glibc openSUSE Tumbleweed 2.24-2.3

opensuse advisories openSUSE-SU-2024:10154-1

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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-2013-7423 updated 2026-11-05 cvss 1.2

glibc: getaddrinfo() writes DNS queries to random file descriptors under high load

Red Hat Enterprise Linux Client (v. 7) nscd 2.17-105.el7, glibc 2.17-105.el7, glibc-utils 2.17-105.el7, glibc-common 2.17-105.el7, glibc-debuginfo-common 2.17-105.el7 Red Hat Enterprise Linux Client Optional (v. 7) glibc-debuginfo-common 2.17-105.el7 Red Hat Enterprise Linux ComputeNode (v. 7) nscd 2.17-105.el7, glibc 2.17-105.el7, glibc-utils 2.17-105.el7, glibc-common 2.17-105.el7, glibc-debuginfo-common 2.17-105.el7
fixed: vendor fix RHSA-2015:2199
Red Hat Enterprise Linux ComputeNode EUS (v. 7.1) nscd 2.17-79.el7_1, glibc 2.17-79.el7_1, glibc-utils 2.17-79.el7_1, glibc-common 2.17-79.el7_1, glibc-debuginfo-common 2.17-79.el7_1
fixed: vendor fix RHSA-2015:2589
Red Hat Enterprise Linux ComputeNode Optional (v. 7) glibc-debuginfo-common 2.17-105.el7
fixed: vendor fix RHSA-2015:2199
Red Hat Enterprise Linux ComputeNode Optional EUS (v. 7.1) glibc-debuginfo-common 2.17-79.el7_1
fixed: vendor fix RHSA-2015:2589
Red Hat Enterprise Linux Desktop (v. 6) nscd 2.12-1.149.el6_6.7, glibc 2.12-1.149.el6_6.7, glibc-utils 2.12-1.149.el6_6.7, glibc-common 2.12-1.149.el6_6.7, glibc-debuginfo-common 2.12-1.149.el6_6.7 Red Hat Enterprise Linux Desktop Optional (v. 6) glibc-debuginfo-common 2.12-1.149.el6_6.7 Red Hat Enterprise Linux HPC Node (v. 6) nscd 2.12-1.149.el6_6.7, glibc 2.12-1.149.el6_6.7, glibc-utils 2.12-1.149.el6_6.7, glibc-common 2.12-1.149.el6_6.7, glibc-debuginfo-common 2.12-1.149.el6_6.7 Red Hat Enterprise Linux HPC Node Optional (v. 6) glibc-debuginfo-common 2.12-1.149.el6_6.7 Red Hat Enterprise Linux Server (v. 6) nscd 2.12-1.149.el6_6.7, glibc 2.12-1.149.el6_6.7, glibc-utils 2.12-1.149.el6_6.7, glibc-common 2.12-1.149.el6_6.7, glibc-debuginfo-common 2.12-1.149.el6_6.7
fixed: vendor fix RHSA-2015:0863
Red Hat Enterprise Linux Server (v. 7) nscd 2.17-105.el7, glibc 2.17-105.el7, glibc-utils 2.17-105.el7, glibc-common 2.17-105.el7, glibc-debuginfo-common 2.17-105.el7
fixed: vendor fix RHSA-2015:2199
Red Hat Enterprise Linux Server AUS (v. 6.5) nscd 2.12-1.132.el6_5.8, glibc 2.12-1.132.el6_5.8, glibc-utils 2.12-1.132.el6_5.8, glibc-common 2.12-1.132.el6_5.8, glibc-debuginfo-common 2.12-1.132.el6_5.8
fixed: vendor fix RHSA-2016:1207
Red Hat Enterprise Linux Server EUS (v. 7.1) nscd 2.17-79.el7_1, glibc 2.17-79.el7_1, nscd 2.17-79.ael7b_1, glibc 2.17-79.ael7b_1, glibc-utils 2.17-79.el7_1, glibc-common 2.17-79.el7_1, +4 more
fixed: vendor fix RHSA-2015:2589

show 9 more

Red Hat Enterprise Linux Server Optional (v. 6) glibc-debuginfo-common 2.12-1.149.el6_6.7
fixed: vendor fix RHSA-2015:0863
Red Hat Enterprise Linux Server Optional (v. 7) glibc-debuginfo-common 2.17-105.el7
fixed: vendor fix RHSA-2015:2199
Red Hat Enterprise Linux Server Optional AUS (v. 6.5) glibc 2.12-1.132.el6_5.8, glibc-debuginfo-common 2.12-1.132.el6_5.8
fixed: vendor fix RHSA-2016:1207
Red Hat Enterprise Linux Server Optional EUS (v. 7.1) glibc-debuginfo-common 2.17-79.el7_1, glibc-debuginfo-common 2.17-79.ael7b_1
fixed: vendor fix RHSA-2015:2589
Red Hat Enterprise Linux Workstation (v. 6) nscd 2.12-1.149.el6_6.7, glibc 2.12-1.149.el6_6.7, glibc-utils 2.12-1.149.el6_6.7, glibc-common 2.12-1.149.el6_6.7, glibc-debuginfo-common 2.12-1.149.el6_6.7
fixed: vendor fix RHSA-2015:0863
Red Hat Enterprise Linux Workstation (v. 7) nscd 2.17-105.el7, glibc 2.17-105.el7, glibc-utils 2.17-105.el7, glibc-common 2.17-105.el7, glibc-debuginfo-common 2.17-105.el7
fixed: vendor fix RHSA-2015:2199
Red Hat Enterprise Linux Workstation Optional (v. 6) glibc-debuginfo-common 2.12-1.149.el6_6.7
fixed: vendor fix RHSA-2015:0863
Red Hat Enterprise Linux Workstation Optional (v. 7) glibc-debuginfo-common 2.17-105.el7
fixed: vendor fix RHSA-2015:2199
Red Hat Enterprise Linux 5 glibc
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

5.81% chance of exploitation in the next 30 days, higher than 93% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
NVD	2.0	5.0	AV:N/AC:L/Au:N/C:N/I:P/A:N

Classification

Weakness

CWE-17 DEPRECATED: Code

References

lists.opensuse.org /opensuse-updates/2015-02/msg00089.html
vendor-advisory, third-party-advisory
security.gentoo.org /glsa/201602-02
vendor-advisory, third-party-advisory
ubuntu.com /usn/USN-2519-1
vendor-advisory, third-party-advisory
rhn.redhat.com /errata/RHSA-2015-0863.html
vendor-advisory
access.redhat.com /errata/RHSA-2016:1207
vendor-advisory, third-party-advisory
github.com /golang/go/issues/6336
third-party-advisory
openwall.com /lists/oss-security/2015/01/28/20
mailing-list, third-party-advisory
sourceware.org /bugzilla/show_bug.cgi?id=15946
issue-tracking
securityfocus.com /bid/72844
vdb-entry, third-party-advisory
seclists.org /fulldisclosure/2021/Sep/0
mailing-list
packetstormsecurity.com /files/164014/Moxa-Command-Injection-Cross-Site-Scripting-Vulnerable-Software.html

Sources

CVE List CVE-2013-7423
NVD CVE-2013-7423

Fencer Intel 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.