No exploitation reportedFix available

CVE-2023-4527

No exploitation reported by the sources we read.

Published2023-09-18
WeaknessCWE-121 · CWE-125

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A flaw was found in glibc. When the getaddrinfo function is called with the AF_UNSPEC address family and the system is configured with no-aaaa mode via /etc/resolv.conf, a DNS response via TCP larger than 2048 bytes can potentially disclose stack contents through the function returned address data, and may cause a crash.

Timeline

dates in UTC

2023-09-1817:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2023-4527?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2023-4527?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Fedoraproject fedora

Branch	Affected	Fixed in	Source
37.x	= 37	no fix published	NVD
38.x	= 38	no fix published	NVD
39.x	= 39	no fix published	NVD

Gnu glibc

Branch	Affected	Fixed in	Source
2.38	≥ 2.38, < 2.38.19	2.38.19	NVD
2.37	≥ 2.37, < 2.37.38	2.37.38	NVD
2.36	≥ 2.36, < 2.36.113	2.36.113	NVD

Redhat enterprise linux

Branch	Affected	Fixed in	Source
8.0	= 8.0	no fix published	NVD
9.0	= 9.0	no fix published	NVD

24 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

glibcAlmaLinux:9all versions · fixed in 2.34-60.el9_2.7and 214 other packages
glibcAlmaLinux:8all versions · fixed in 2.28-225.el8_8.6and 213 other packages

Vendor advisories

CVE-2023-4527 Red Hat Product Security2,031 products fixed
glibc: Stack read overflow in getaddrinfo in no-aaaa mode
ICSA-25-162-05 CISA5 known affected
Siemens SIMATIC S7-1500 CPU family
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) · +2 more
SSA-082556 Siemens ProductCERT5 known affected
SSA-082556: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP V3.1.5
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= V3.1.5 · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= V3.1.5 · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= V3.1.5 · +2 more
RHSA-2023:5455 Red Hat Product Security1,017 products fixed
Red Hat Security Advisory: glibc security update
RHSA-2023:5453 Red Hat Product Security1,014 products fixed
Red Hat Security Advisory: glibc security update
ICSA-23-166-10 CISA1 known affected
Siemens SIMATIC S7-1500 TM MFP BIOS
SIMATIC S7-1500 TM MFP - BIOS

1 more advisory

Full record on NVD

Fix

Vendor fix Red Hat Product Security RHSA-2023:5455 · 1,017 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 For the update to take effect, all services linked to the glibc library must be restarted, or the system rebooted.
Vendor fix Red Hat Product Security RHSA-2023:5453 · 1,014 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
Vendor fix Siemens ProductCERT SSA-831302 · 1 productUpdate to V1.3.0 or later version
Vendor fix CISA ICSA-23-166-10 · 1 productUpdate to V1.3.0 or later version
Workaround from the vendor Red Hat Product Security RHSA-2023:5455 · 1,017 productsRemoving the no-aaaa diagnostic option from /etc/resolv.conf will mitigate this flaw.
Workaround from the vendor Siemens ProductCERT SSA-831302 · 1 productOnly build and run applications from trusted sources

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionnone2024-12-03
OpenCVESSVC decisionnone—
CNACVSS 3.16.5read 2026-10-23
NVDCVSS 3.16.5read 2026-10-23
CNAweakness (CWE)CWE-121read 2026-10-23
NVDweakness (CWE)CWE-125read 2026-10-23
FIRST EPSSEPSS score1.7 %2026-10-23
OSVaffected packages—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H
Published: 2023-09-18
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2023-4527?

Is CVE-2023-4527 actively exploited?

Active exploitation of CVE-2023-4527 has not been confirmed. Its EPSS score was 1.7% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2023-4527?

CVE-2023-4527 has a CVSS v3 base score of 6.5 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H.

Running glibc? Hear about its next vulnerability

Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

Get alerts for this product CISA KEV additions, October 2026 Search CVEs

No credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
Running this software? Vulnerability monitoring alerts you to new vulnerabilities in your products.

Related vulnerabilities

Same product first, then the same vendor advisory and the same publication week.

Back to CVE Database