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Fencer Vulns
high 7.5

CVE-2021-27218 json

An issue was discovered in GNOME GLib before 2.66.7 and 2.67.x before 2.67.4

published 2021-02-15 5 y ago modified 2026-10-14 26 d ago also EUVD-2021-13983 , JLSEC-2025-156

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
4.1%
EPSS 4.1% chance of exploitation in 30 days, percentile 90%
public exploits
0
none known

Summary

An issue was discovered in GNOME GLib before 2.66.7 and 2.67.x before 2.67.4. If g_byte_array_new_take() was called with a buffer of 4GB or more on a 64-bit platform, the length would be truncated modulo 2**32, causing unintended length truncation.

Patch / fix

  • julia Glib_jll 2.68.1+0
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.5
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP V3.1.5
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP V3.1.5
  • glib2.0 Debian 14, Debian 13, Debian 12 2.66.7-1

debian advisories DEBIAN-CVE-2021-27218

  • glib2.0 Ubuntu 16.04 LTS 2.48.2-0ubuntu4.7
  • glib2.0 Ubuntu 18.04 LTS 2.56.4-0ubuntu0.18.04.7
  • glib2.0 Ubuntu 20.04 LTS 2.64.6-1~ubuntu20.04.2

ubuntu advisories UBUNTU-CVE-2021-27218

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

  • mingw-glib2 RHEL 8 2.66.7-2.el8
  • mingw32-glib2 RHEL 8 2.66.7-2.el8
  • mingw64-glib2 RHEL 8 2.66.7-2.el8
  • glib2 RHEL 8 2.56.4-10.el8_4.1
  • glib2-fam RHEL 8 2.56.4-10.el8_4.1
  • glib2-tests RHEL 8 2.56.4-10.el8_4.1

red hat advisories RHSA-2021:4526RHSA-2021:3058

  • glib2 SLES for SAP 15 SP1, SLES for SAP 15, SLES 15-LTSS +10 more 2.54.3-4.24.1
  • glib2 SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +15 more 2.48.2-12.22.1
  • glib2 SLE Module for Basesystem 15 SP2, SLE Micro 5.0 2.62.6-3.6.1

suse advisories SUSE-SU-2021:0890-1SUSE-SU-2021:0801-1SUSE-SU-2021:0778-1

  • glib2 openSUSE Leap 15.2 2.62.6-lp152.2.6.1

opensuse advisories openSUSE-SU-2021:0406-1

  • mingw32-glib2 AlmaLinux 8 2.66.7-2.el8
  • mingw64-glib2 AlmaLinux 8 2.66.7-2.el8

almalinux advisories ALSA-2021:4526

  • glib2 Rocky Linux 8 2.56.4-10.el8_4.1

rocky linux advisories RLSA-2021:3058

  • glib Alpine 3.13 2.66.7-r0

alpine advisories ALPINE-CVE-2021-27218

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • glib CBL-Mariner 2.0 2.60.1-5

azure linux advisories AZL-6437

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

  • glib2 Arch Linux 2.66.7-1

arch linux advisories AVG-1575

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-2021-27218 updated cvss 7.5

glib: integer overflow in g_byte_array_new_take function when called with a buffer of 4GB or more on a 64-bit platform

  • Red Hat Enterprise Linux 6 glib2, firefox, thunderbird Red Hat Enterprise Linux 7 glib2, glib2-fam, glib2-tests
    affected: no fix planned “Out of support scope”
  • Red Hat CodeReady Linux Builder (v. 8) mingw-glib2 2.66.7-2.el8, mingw32-glib2 2.66.7-2.el8, mingw64-glib2 2.66.7-2.el8 Red Hat Enterprise Linux BaseOS (v. 8) glib2 2.56.4-10.el8_4.1, glib2-fam 2.56.4-10.el8_4.1, glib2-tests 2.56.4-10.el8_4.1
    fixed: vendor fix RHSA-2021:3058
  • Red Hat Enterprise Linux 9 glib2, glib2-tests, mingw-glib2, mingw32-glib2, mingw64-glib2
    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

cisa ICSA-23-348-10 updated cvss 7.5

Siemens SIMATIC S7-1500

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.0, < 3.1.5 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.0, < 3.1.5
    affected: fixed in V3.1.5, mitigation support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

Exploit prediction

4.08% chance of exploitation in the next 30 days, higher than 90% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
julia Glib_jll
<2.68.1+0
2.68.1+0

Affected products

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

Classification

Weakness
  • CWE-681 Incorrect Conversion between Numeric Types

References

Sources

Fencer Vulns 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.