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Fencer Vulns
high 8.8

CVE-2021-30558 in the critical feed json

Insufficient policy enforcement in content security policy in Google Chrome prior to 91.0.4472.77 allowed a remote attacker to bypass conte…

published 2023-01-02 3 y ago modified 2026-06-17 4 mo ago also EUVD-2021-17479

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
11.5%
EPSS 11.5% chance of exploitation in 30 days, percentile 96%
public exploits
0
none known

Summary

Insufficient policy enforcement in content security policy in Google Chrome prior to 91.0.4472.77 allowed a remote attacker to bypass content security policy via a crafted HTML page. (Chrome security severity: Medium)

Patch / fix

  • Google Chrome 91.0.4472.77
  • chromium Debian 14, Debian 13, Debian 12 93.0.4577.82-1

debian advisories DEBIAN-CVE-2021-30558

  • chromium-browser Ubuntu 18.04 LTS 91.0.4472.77-0ubuntu0.18.04.1

ubuntu advisories UBUNTU-CVE-2021-30558

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

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-2021-30558 updated cvss 6.5

chromium-browser: Insufficient policy enforcement in content security policy

  • 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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
2 y ago

Exploit prediction

11.49% chance of exploitation in the next 30 days, higher than 96% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • crbug.com https://crbug.com/916326 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

  • Google Chrome

Classification

Technology feeds

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.