CVE-2023-4527Network attack vector

Stack disclosure and crash via oversized DNS response

Published Sep 18, 2023 · Updated Jul 14, 2026

Stack over-read in glibc getaddrinfo allows remote attackers to disclose stack data through returned addresses or crash the caller. In _nss_dns_gethostbyname4_r, __res_context_search stores only 2,048 bytes but returns the full DNS packet length, so subsequent parsing reads past the stack buffer. Exposure requires AF_UNSPEC, no-aaaa in /etc/resolv.conf, and an oversized TCP DNS response; integrity impact is not reported.

CVSS severity6.5
Medium
EPSS probability1.67%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack over-read in glibc getaddrinfo allows remote attackers to disclose stack data through returned addresses or crash the caller. In _nss_dns_gethostbyname4_r, __res_context_search stores only 2,048 bytes but returns the full DNS packet length, so subsequent parsing reads past the stack buffer. Exposure requires AF_UNSPEC, no-aaaa in /etc/resolv.conf, and an oversized TCP DNS response; integrity impact is not reported.

The record

CVE
CVE-2023-4527
Published
Sep 18, 2023
Updated
Jul 14, 2026
Vendor
Red Hat
Product
Red Hat Enterprise Linux 8
Classifications
CWE-121, CWE-125, T1499.004
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 <*
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.
Siemens · SIMATIC S7-1500 CPU 1518-4 PN/DP MFPversion=V3.1.5 <*

Published CVSS scores

6.5Red HatCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H
6.5NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
CWE-125Out-of-bounds Read
T1499.004Application or System Exploitation

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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