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Fencer Intel
medium 5.3

CVE-2016-1939 json

Mozilla Firefox before 44.0 stores cookies with names containing vertical tab characters, which allows remote attackers to obtain sensitive…

published 2016-01-31 10 y ago modified 2026-06-17 4 mo ago also EUVD-2016-3028

cvss
5.3
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.8%
EPSS 1.8% chance of exploitation in 30 days, percentile 78%
public exploits
0
none known

Summary

Mozilla Firefox before 44.0 stores cookies with names containing vertical tab characters, which allows remote attackers to obtain sensitive information by reading HTTP Cookie headers. NOTE: this vulnerability exists because of an incomplete fix for CVE-2015-7208.

Patch / fix

  • firefox Ubuntu 14.04 LTS 44.0+build3-0ubuntu0.14.04.1

ubuntu advisories UBUNTU-CVE-2016-1939

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

  • MozillaFirefox openSUSE Tumbleweed 50.1.0-1.1

opensuse advisories openSUSE-SU-2024:10071-1

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-2016-1939 updated cvss 4.3

Mozilla: Firefox allows for control characters to be set in cookie names (MFSA 2016-04)

  • Red Hat Enterprise Linux 5 firefox, thunderbird 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

1.76% chance of exploitation in the next 30 days, higher than 78% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.0 5.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N

Classification

Weakness
  • CWE-200 Exposure of Sensitive Information to an Unauthorized Actor

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.