Inappropriate implementation in iframe sandbox in Google Chrome prior to 88.0.4324.96 allowed a remote attacker to bypass navigation restri…

published 2021-02-09 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-8530

cvss: 6.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 5.1%; EPSS 5.1% chance of exploitation in 30 days, percentile 92%
public exploits: 0; none known

Inappropriate implementation in iframe sandbox in Google Chrome prior to 88.0.4324.96 allowed a remote attacker to bypass navigation restrictions via a crafted HTML page.

Patch / fix

fixed in 1 distros 4 links 1

Google Chrome 88.0.4324.96

debian ubuntu opensuse arch linux

chromium Debian 14, Debian 13, Debian 12 88.0.4324.96-0.1

debian advisories DEBIAN-CVE-2021-21139

chromium-browser Ubuntu 16.04 LTS 89.0.4389.82-0ubuntu0.16.04.1
chromium-browser Ubuntu 18.04 LTS 89.0.4389.82-0ubuntu0.18.04.1

ubuntu advisories UBUNTU-CVE-2021-21139

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

chromium openSUSE Tumbleweed 93.0.4577.82-1.1
chromium openSUSE Tumbleweed 113.0.5672.92-1.1
chromium Package Hub 15 SP2 88.0.4324.96-bp152.2.53.1
chromium Package Hub 15 SP1 88.0.4324.96-bp151.3.156.1
chromium openSUSE Leap 15.2 88.0.4324.96-lp152.2.66.1
chromium openSUSE Leap 15.1 88.0.4324.96-lp151.2.171.1

opensuse advisories openSUSE-SU-2024:10681-1 openSUSE-SU-2024:12948-1 openSUSE-SU-2021:0186-1 openSUSE-SU-2021:0177-1 openSUSE-SU-2021:0173-1 openSUSE-SU-2021:0166-1

chromium Arch Linux 88.0.4324.96-1
vivaldi Arch Linux 3.6.2165.36-1

arch linux advisories AVG-1477 AVG-1478

crbug.com/937131 advisory

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-2021-21139 updated 2025-11-21 cvss 4.3

chromium-browser: Inappropriate implementation in iframe sandbox

Red Hat All currently supported Red Hat products
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

Exploit prediction

5.12% chance of exploitation in the next 30 days, higher than 92% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

crbug.com https://crbug.com/937131 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
NVD	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
NVD	2.0	4.3	AV:N/AC:M/Au:N/C:N/I:P/A:N

Affected products

Google Chrome

Classification

Weakness

CWE-1021 Improper Restriction of Rendered UI Layers or Frames

Technology feeds

Google Chrome rss critical rss

References

crbug.com /937131
exploit, issue-tracking, patch, vendor-advisory
chromereleases.googleblog.com /2021/01/stable-channel-update-for-desktop_19.html
release-notes, vendor-advisory
msrc.microsoft.com /update-guide/en-US/vulnerability/CVE-2021-21139
third-party-advisory

Sources

CVE List CVE-2021-21139
NVD CVE-2021-21139

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.

Summary