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Fencer Vulns
high 8.8

CVE-2018-12370 json

In Reader View SameSite cookie protections are not checked on exiting.

published 2018-10-18 8 y ago modified 2026-06-17 4 mo ago also EUVD-2018-4344

cvss
8.8
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 66%
public exploits
0
none known

Summary

In Reader View SameSite cookie protections are not checked on exiting. This allows for a payload to be triggered when Reader View is exited if loaded by a malicious site while Reader mode is active, bypassing CSRF protections. This vulnerability affects Firefox < 61.

Patch / fix

  • Mozilla Firefox 61
  • firefox Ubuntu 14.04 LTS 61.0+build3-0ubuntu0.14.04.2
  • firefox Ubuntu 16.04 LTS 61.0+build3-0ubuntu0.16.04.2
  • firefox Ubuntu 18.04 LTS 61.0+build3-0ubuntu0.18.04.1

ubuntu advisories UBUNTU-CVE-2018-12370

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

  • firefox-esr openSUSE Tumbleweed 128.5.1-1.1
  • MozillaFirefox openSUSE Tumbleweed 92.0-1.2

opensuse advisories openSUSE-SU-2024:14572-1openSUSE-SU-2024:10600-1

  • firefox Arch Linux 61.0-1

arch linux advisories AVG-727

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-2018-12370 updated cvss 8.8

Mozilla: SameSite cookie protections bypassed when exiting Reader View

  • Red Hat Enterprise Linux 6 firefox, thunderbird Red Hat Enterprise Linux 7 firefox, thunderbird
    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

1.13% chance of exploitation in the next 30 days, higher than 66% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.0 8.8 CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P

Affected products

  • Mozilla Firefox

Classification

Weakness
  • CWE-352 Cross-Site Request Forgery

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.