No exploitation reportedFix available

CVE-2021-27218

Q: Is CVE-2021-27218 actively exploited?

Active exploitation of CVE-2021-27218 has not been confirmed. Its EPSS score was 4.1% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2021-27218?

CVE-2021-27218 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

No exploitation reported by the sources we read.

Published2021-02-15
WeaknessCWE-681

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

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.

Timeline

dates in UTC

2021-02-1517:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 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-2021-27218?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-27218?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
33.x	= 33	no fix published	NVD
34.x	= 34	no fix published	NVD

Gnome glib

Branch	Affected	Fixed in	Source
2.67	≥ 2.67.0, < 2.67.4	2.67.4	NVD
2.66	< 2.66.7	2.66.7	NVD

Broadcom brocade fabric operating system firmware

Branch	Affected	Fixed in	Source
—	all versions	no fix published	NVD

4 more products in the sources.

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

Fix

Advisories and patches

gitlab.gnome.orgPatch · Vendor Advisory
gitlab.gnome.orgPatch · Vendor Advisory

Detection

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

Sources

NVDCVSS 3.17.5read 2026-10-23
NVDCVSS 2.05read 2026-10-23
NVDweakness (CWE)CWE-681read 2026-10-23
FIRST EPSSEPSS score4.1 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: 2021-02-15
Last Modified: 2026-10-14
NVD status: Modified

Frequently asked questions

What is CVE-2021-27218?

Is CVE-2021-27218 actively exploited?

Active exploitation of CVE-2021-27218 has not been confirmed. Its EPSS score was 4.1% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-27218?

CVE-2021-27218 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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