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Fencer Intel
medium 6.5

CVE-2021-21163 json

Insufficient data validation in Reader Mode in Google Chrome on iOS prior to 89.0.4389.72 allowed a remote attacker to leak cross-origin da…

published 5y ago modified 4mo ago also EUVD-2021-8554

cvss
6.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 61%
public exploits
0
none known

Summary

Insufficient data validation in Reader Mode in Google Chrome on iOS prior to 89.0.4389.72 allowed a remote attacker to leak cross-origin data via a crafted HTML page and a malicious server.

Patch / fix

  • Google Chrome 89.0.4389.72
  • chromium Debian 14, Debian 13, Debian 12 89.0.4389.82-1

debian advisories DEBIAN-CVE-2021-21163

  • 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-2021-21163

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 89.0.4389.72-bp152.2.62.1
  • chromium openSUSE Leap 15.2 89.0.4389.72-lp152.2.77.1

opensuse advisories openSUSE-SU-2024:10681-1openSUSE-SU-2024:12948-1openSUSE-SU-2021:0401-1openSUSE-SU-2021:0392-1

  • chromium Alpine 3.24, Alpine 3.23, Alpine 3.22 +8 more 89.0.4389.72-r0

alpine advisories ALPINE-CVE-2021-21163

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

  • chromium Arch Linux 89.0.4389.72-1
  • vivaldi Arch Linux 3.7.2218.45-1

arch linux advisories AVG-1631AVG-1633

Is CVE-2021-21163 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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-2021-21163 updated cvss 8.8

chromium-browser: Insufficient data validation in Reader Mode

  • 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

0.94% chance of exploitation in the next 30 days, higher than 61% of all scored CVEs (FIRST EPSS, 2026-11-09).

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:H/I:N/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:P/I:N/A:N

Affected products

  • Google Chrome

Classification

Weakness
Technology feeds

References

Sources

Fencer Intel 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.