CVE-2023-4806 | Glibc: potential use-after-free in getaddrinfo()

A flaw has been identified in glibc. In an extremely rare situation, the getaddrinfo function may access memory that has been freed, resulting in an application crash. This issue is only exploitable when a NSS module implements only the _nss_*_gethostbyname2_r and _nss_*_getcanonname_r hooks without implementing the _nss_*_gethostbyname3_r hook. The resolved name should return a large number of IPv6 and IPv4, and the call to the getaddrinfo function should have the AF_INET6 address family with AI_CANONNAME, AI_ALL and AI_V4MAPPED as flags.

Published: 2023-09-18 Last update: 2026-05-12 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-4806 is rated Moderate Risk (52.7/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.90%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2023-4806

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-01-07 1.75% 1.90% +0.15%
2 2026-01-05 1.95% 1.75% -0.20%
3 2025-11-28 — 1.95% —

Full EPSS history (21 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-4806

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.9 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.2 3.6 [email protected]
5.9 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.2 3.6 [email protected]

Weakness enumeration for CVE-2023-4806

GitHub Security Advisory for CVE-2023-4806

GHSA-5f52-v49r-796w · Severity: medium — A flaw was found in glibc. In an extremely rare situation, the getaddrinfo function may access...

OS Trackers for CVE-2023-4806

vendor priority summary link
debian not yet assigned CVE-2023-4806 not yet assigned priority: Debian including 1 source packages (glibc), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 4, open 1. https://security-tracker.debian.org/tracker/CVE-2023-4806
gentoo high CVE-2023-4806: 1 GLSA(s) (202310-03), 1 atom(s) (sys-libs/glibc); latest impact high. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2023-4806
redhat medium — https://access.redhat.com/security/cve/CVE-2023-4806
suse medium CVE-2023-4806 severity moderate: SUSE including 514 source package names (compat-libpthread-nonshared-2.28-225.el8_8.6, glibc, …), 859 product×package rows across 52 product lines (SUSE CaaS Platform 4.0, SUSE Enterprise Storage 7.1, … (52 product lines)): Fixed 496, Known Not Affected 363. https://www.suse.com/security/cve/CVE-2023-4806/
ubuntu low CVE-2023-4806 low priority: Ubuntu including 2 source packages (eglibc, glibc), 24 status rows across 12 suites (bionic, focal, jammy, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 10, released 10, needs-triage 3, ignored 1. https://ubuntu.com/security/CVE-2023-4806

Affected software / configurations for CVE-2023-4806

Vendor Product Version Raw CPE
gnu glibc 2.33 cpe:2.3:a:gnu:glibc:2.33:*:*:*:*:*:*:*
redhat codeready_linux_builder_eus 9.2 cpe:2.3:a:redhat:codeready_linux_builder_eus:9.2:*:*:*:*:*:*:*
redhat codeready_linux_builder_eus_for_power_little_endian 9.0_ppc64le cpe:2.3:a:redhat:codeready_linux_builder_eus_for_power_little_endian:9.0_ppc64le:*:*:*:*:*:*:*
redhat codeready_linux_builder_eus_for_power_little_endian_eus 9.2_ppc64le cpe:2.3:a:redhat:codeready_linux_builder_eus_for_power_little_endian_eus:9.2_ppc64le:*:*:*:*:*:*:*
redhat codeready_linux_builder_for_arm64 9.0_aarch64 cpe:2.3:a:redhat:codeready_linux_builder_for_arm64:9.0_aarch64:*:*:*:*:*:*:*
redhat codeready_linux_builder_for_arm64_eus 9.2_aarch64 cpe:2.3:a:redhat:codeready_linux_builder_for_arm64_eus:9.2_aarch64:*:*:*:*:*:*:*
redhat codeready_linux_builder_for_ibm_z_systems 9.0_s390x cpe:2.3:a:redhat:codeready_linux_builder_for_ibm_z_systems:9.0_s390x:*:*:*:*:*:*:*
redhat codeready_linux_builder_for_ibm_z_systems_eus 9.2_s390x cpe:2.3:a:redhat:codeready_linux_builder_for_ibm_z_systems_eus:9.2_s390x:*:*:*:*:*:*:*
redhat enterprise_linux 7.0 cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
redhat enterprise_linux 8.0 cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
redhat enterprise_linux 9.0 cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*
redhat enterprise_linux_eus 8.8 cpe:2.3:o:redhat:enterprise_linux_eus:8.8:*:*:*:*:*:*:*
redhat enterprise_linux_eus 9.2 cpe:2.3:o:redhat:enterprise_linux_eus:9.2:*:*:*:*:*:*:*
redhat enterprise_linux_for_arm_64 9.0_aarch64 cpe:2.3:o:redhat:enterprise_linux_for_arm_64:9.0_aarch64:*:*:*:*:*:*:*
redhat enterprise_linux_for_arm_64_eus 9.2_aarch64 cpe:2.3:o:redhat:enterprise_linux_for_arm_64_eus:9.2_aarch64:*:*:*:*:*:*:*
redhat enterprise_linux_for_ibm_z_systems 8.0_s390x cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems:8.0_s390x:*:*:*:*:*:*:*
redhat enterprise_linux_for_ibm_z_systems_eus 8.8_s390x cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus:8.8_s390x:*:*:*:*:*:*:*
redhat enterprise_linux_for_ibm_z_systems_eus_s390x 9.2 cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus_s390x:9.2:*:*:*:*:*:*:*
redhat enterprise_linux_for_ibm_z_systems_s390x 9.2 cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_s390x:9.2:*:*:*:*:*:*:*
redhat enterprise_linux_for_power_little_endian 8.0_ppc64le cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian:8.0_ppc64le:*:*:*:*:*:*:*
redhat enterprise_linux_for_power_little_endian 9.2_ppc64le cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian:9.2_ppc64le:*:*:*:*:*:*:*
redhat enterprise_linux_for_power_little_endian_eus 8.8_ppc64le cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:8.8_ppc64le:*:*:*:*:*:*:*
redhat enterprise_linux_for_power_little_endian_eus 9.2_ppc64le cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:9.2_ppc64le:*:*:*:*:*:*:*
redhat enterprise_linux_server_aus 9.2 cpe:2.3:o:redhat:enterprise_linux_server_aus:9.2:*:*:*:*:*:*:*
redhat enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions 9.2_ppc64le cpe:2.3:o:redhat:enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions:9.2_ppc64le:*:*:*:*:*:*:*
redhat enterprise_linux_tus 8.8 cpe:2.3:o:redhat:enterprise_linux_tus:8.8:*:*:*:*:*:*:*
fedoraproject fedora 37 cpe:2.3:o:fedoraproject:fedora:37:*:*:*:*:*:*:*
fedoraproject fedora 38 cpe:2.3:o:fedoraproject:fedora:38:*:*:*:*:*:*:*
fedoraproject fedora 39 cpe:2.3:o:fedoraproject:fedora:39:*:*:*:*:*:*:*

References for CVE-2023-4806

URL Tags
https://access.redhat.com/errata/RHBA-2024:2413
https://access.redhat.com/errata/RHSA-2023:5453 Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:5455 Third Party Advisory
https://access.redhat.com/errata/RHSA-2023:7409
https://access.redhat.com/security/cve/CVE-2023-4806 Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2237782 Issue Tracking Third Party Advisory
http://www.openwall.com/lists/oss-security/2023/10/03/4
http://www.openwall.com/lists/oss-security/2023/10/03/5
http://www.openwall.com/lists/oss-security/2023/10/03/6
http://www.openwall.com/lists/oss-security/2023/10/03/8
https://lists.fedoraproject.org/archives/list/[email protected]/message/4DBUQRRPB47TC3NJOUIBVWUGFHBJAFDL/
https://lists.fedoraproject.org/archives/list/[email protected]/message/DFG4P76UHHZEWQ26FWBXG76N2QLKKPZA/
https://lists.fedoraproject.org/archives/list/[email protected]/message/NDAQWHTSVOCOZ5K6KPIWKRT3JX4RTZUR/
https://security.gentoo.org/glsa/202310-03
https://security.netapp.com/advisory/ntap-20240125-0008/
https://cert-portal.siemens.com/productcert/html/ssa-082556.html
https://cert-portal.siemens.com/productcert/html/ssa-831302.html
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