CVE-2023-4806Network attack vector

Application crash via stale getaddrinfo canonical-name pointer

Published Sep 18, 2023 · Updated Jul 14, 2026

Use-after-free in glibc getaddrinfo allows remote attackers to crash applications through crafted name-resolution results. During repeated NSS lookups, tmpbuf resizing can free storage still referenced by res->at->name, which getcanonname_r then dereferences. Exploitation requires an NSS module with gethostbyname2_r and getcanonname_r but not gethostbyname3_r, many IPv4 and IPv6 results, and an AF_INET6 request using AI_CANONNAME, AI_ALL, and AI_V4MAPPED.

CVSS severity5.9
Medium
EPSS probability1.61%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in glibc getaddrinfo allows remote attackers to crash applications through crafted name-resolution results. During repeated NSS lookups, tmpbuf resizing can free storage still referenced by res->at->name, which getcanonname_r then dereferences. Exploitation requires an NSS module with gethostbyname2_r and getcanonname_r but not gethostbyname3_r, many IPv4 and IPv6 results, and an AF_INET6 request using AI_CANONNAME, AI_ALL, and AI_V4MAPPED.

The record

CVE
CVE-2023-4806
Published
Sep 18, 2023
Updated
Jul 14, 2026
Vendor
Red Hat
Product
Red Hat Enterprise Linux 8
Classifications
CWE-416, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 18, 2023CVE publishedPublication date reported by the CVE source.
  2. Jul 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Red Hat · Red Hat Enterprise Linux 8Affected versions are unavailable in this record.
Siemens · SIPLUS S7-1500 CPU 1518-4 PN/DP MFPversion=V3.1.5 <*
Red Hat · Red Hat Enterprise Linux 7Affected versions are unavailable in this record.
Siemens · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPversion=V3.1.5 <*
Red Hat · Red Hat Enterprise Linux 9Affected versions are unavailable in this record.
Red Hat · Red Hat Enterprise Linux 8.6 Extended Update SupportAffected versions are unavailable in this record.
Siemens · SIMATIC S7-1500 CPU 1518-4 PN/DP MFPversion=V3.1.5 <*
Red Hat · Red Hat Virtualization 4 for Red Hat Enterprise Linux 8Affected versions are unavailable in this record.

Published CVSS scores

5.9Red HatCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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