medium 4.3

CVE-2026-0887 json

Clickjacking issue, information disclosure in the PDF Viewer component

published 2026-01-13 9 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-2078

cvss: 4.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 25%
public exploits: 0; none known

Clickjacking issue, information disclosure in the PDF Viewer component. This vulnerability was fixed in Firefox 147, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.

Patch / fix

fixed in 4 distros 7

mozilla firefox 140.7, 147
mozilla firefox_esr 140.7, 147
mozilla thunderbird 140.7, 147
mozilla thunderbird_esr 140.7, 147

debian ubuntu red hat suse opensuse almalinux rocky linux

firefox-esr Debian 12 140.7.0esr-1~deb12u1
firefox-esr Debian 13 140.7.0esr-1~deb13u1
firefox-esr Debian 14 140.7.0esr-1
thunderbird Debian 12 1:140.7.0esr-1~deb12u1
thunderbird Debian 13 1:140.7.0esr-1~deb13u1
thunderbird Debian 14 1:140.7.0esr-1

debian advisories DEBIAN-CVE-2026-0887

thunderbird Ubuntu 22.04 LTS 1:140.7.1+build1-0ubuntu0.22.04.1

ubuntu advisories UBUNTU-CVE-2026-0887

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 RHEL 10.1 140.7.0-1.el10_1
thunderbird RHEL 10.1 140.7.0-1.el10_1
thunderbird RHEL 8 140.7.0-1.el8_10
thunderbird RHEL 9 140.7.0-1.el9_7
firefox RHEL 9 140.7.0-1.el9_7
firefox-x11 RHEL 9 140.7.0-1.el9_7
firefox RHEL 8 140.7.0-1.el8_10
firefox enterprise linux eus 10.0 140.7.0-1.el10_0

red hat advisories RHSA-2026:2271 RHSA-2026:2286 RHSA-2026:2231 RHSA-2026:2220 RHSA-2026:2074 RHSA-2026:2070

MozillaFirefox SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +9 more 140.7.0-150200.152.216.1
MozillaThunderbird SLE Workstation Extension 15 SP7, SLE Module for Package Hub 15 SP7, openSUSE Leap 15.6 140.7.0-150200.8.251.1
MozillaFirefox SLES for SAP applications 16.0, SLES 16.0 140.7.0-160000.1.1
MozillaFirefox SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 140.7.0-112.295.1

suse advisories SUSE-SU-2026:0260-1 SUSE-SU-2026:0153-1 SUSE-SU-2026:20086-1 SUSE-SU-2026:0122-1

MozillaThunderbird openSUSE Leap 16.0 140.8.1-bp160.1.1
MozillaThunderbird openSUSE Tumbleweed 140.7.0-1.1
MozillaFirefox openSUSE Leap 16.0 140.7.0-160000.1.1
MozillaFirefox openSUSE Tumbleweed 147.0-1.1
firefox-esr openSUSE Tumbleweed 140.7.0-1.1

opensuse advisories openSUSE-SU-2026:20391-1 openSUSE-SU-2026:10058-1 openSUSE-SU-2026:20041-1 openSUSE-SU-2026:10046-1 openSUSE-SU-2026:10037-1

thunderbird AlmaLinux 8 140.7.0-1.el8_10.alma.1
firefox AlmaLinux 10 140.7.0-1.el10_1
thunderbird AlmaLinux 10 140.7.0-1.el10_1.alma.1
thunderbird AlmaLinux 9 140.7.0-1.el9_7.alma.1
firefox AlmaLinux 8 140.7.0-1.el8_10.alma.1
firefox AlmaLinux 9 140.7.0-1.el9_7.alma.1
firefox-x11 AlmaLinux 9 140.7.0-1.el9_7.alma.1

almalinux advisories ALSA-2026:2220 ALSA-2026:2271 ALSA-2026:2286 ALSA-2026:0924 ALSA-2026:0667 ALSA-2026:0694

thunderbird Rocky Linux 8 140.7.0-1.el8_10
thunderbird Rocky Linux 9 140.7.0-1.el9_7
firefox Rocky Linux 9 140.7.0-1.el9_7
firefox Rocky Linux 8 140.7.0-1.el8_10

rocky linux advisories RLSA-2026:2220 RLSA-2026:0924 RLSA-2026:0694 RLSA-2026:0667

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-2026-0887 updated 2026-11-07 cvss 6.1

firefox: thunderbird: Clickjacking issue, information disclosure in the PDF Viewer component

Red Hat Enterprise Linux 6 firefox, thunderbird Red Hat Enterprise Linux 7 thunderbird
affected: workaround, no fix planned “Out of support scope”
Red Hat Enterprise Linux 10 rhel8/flatpak-runtime, rhel10/firefox-flatpak
affected: workaround, no fix available
Red Hat Enterprise Linux AppStream (v. 8) firefox 140.7.0-1.el8_10, thunderbird 140.7.0-1.el8_10
fixed: vendor fix RHSA-2026:0667
Red Hat Enterprise Linux AppStream (v. 9) firefox 140.7.0-1.el9_7, firefox-x11 140.7.0-1.el9_7, thunderbird 140.7.0-1.el9_7
fixed: vendor fix RHSA-2026:0694
Red Hat Enterprise Linux AppStream (v. 10) firefox 140.7.0-1.el10_1, thunderbird 140.7.0-1.el10_1
fixed: vendor fix RHSA-2026:2271
Red Hat Enterprise Linux AppStream AUS (v. 8.2) firefox 140.7.0-1.el8_2, thunderbird 140.7.0-1.el8_2
fixed: vendor fix RHSA-2026:2074
Red Hat Enterprise Linux AppStream AUS (v.8.4) firefox 140.7.0-1.el8_4, thunderbird 140.7.0-1.el8_4
fixed: vendor fix RHSA-2026:2073
Red Hat Enterprise Linux AppStream AUS (v.8.6) firefox 140.7.0-1.el8_6, thunderbird 140.7.0-1.el8_6 Red Hat Enterprise Linux AppStream E4S (v.8.6) firefox 140.7.0-1.el8_6, thunderbird 140.7.0-1.el8_6
fixed: vendor fix RHSA-2026:2070

show 10 more

Red Hat Enterprise Linux AppStream E4S (v.8.8) firefox 140.7.0-1.el8_8, thunderbird 140.7.0-1.el8_8
fixed: vendor fix RHSA-2026:2069
Red Hat Enterprise Linux AppStream E4S (v.9.0) firefox 140.7.0-1.el9_0, thunderbird 140.7.0-1.el9_0
fixed: vendor fix RHSA-2026:2047
Red Hat Enterprise Linux AppStream E4S (v.9.2) firefox 140.7.0-1.el9_2, firefox-x11 140.7.0-1.el9_2, thunderbird 140.7.0-1.el9_2
fixed: vendor fix RHSA-2026:2044
Red Hat Enterprise Linux AppStream EUS (v. 10.0) firefox 140.7.0-1.el10_0, thunderbird 140.7.0-1.el10_0
fixed: vendor fix RHSA-2026:2271
Red Hat Enterprise Linux AppStream EUS (v.9.4) firefox 140.7.0-1.el9_4, firefox-x11 140.7.0-1.el9_4, thunderbird 140.7.0-1.el9_4
fixed: vendor fix RHSA-2026:2041
Red Hat Enterprise Linux AppStream EUS (v.9.6) firefox 140.7.0-1.el9_6, firefox-x11 140.7.0-1.el9_6, thunderbird 140.7.0-2.el9_6
fixed: vendor fix RHSA-2026:2043
Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) firefox 140.7.0-1.el8_4, thunderbird 140.7.0-1.el8_4
fixed: vendor fix RHSA-2026:2073
Red Hat Enterprise Linux AppStream TUS (v.8.6) firefox 140.7.0-1.el8_6, thunderbird 140.7.0-1.el8_6
fixed: vendor fix RHSA-2026:2070
Red Hat Enterprise Linux AppStream TUS (v.8.8) firefox 140.7.0-1.el8_8, thunderbird 140.7.0-1.el8_8
fixed: vendor fix RHSA-2026:2069
Red Hat Enterprise Linux Server (v. 7 ELS) firefox 140.7.0-1.el7_9
fixed: vendor fix RHSA-2026:2231

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: partial
Assessed: 9 mo ago (2026-01-15)

Exploit prediction

0.33% chance of exploitation in the next 30 days, higher than 25% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CISA ADP	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
CNA	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

Affected products

Mozilla Firefox
Mozilla Thunderbird

Classification

Weakness

CWE-497 Exposure of Sensitive System Information to an Unauthorized Control Sphere

References

mozilla.org /security/advisories/mfsa2026-01/
vendor-advisory
mozilla.org /security/advisories/mfsa2026-03/
vendor-advisory
mozilla.org /security/advisories/mfsa2026-04/
vendor-advisory
mozilla.org /security/advisories/mfsa2026-05/
vendor-advisory
bugzilla.mozilla.org /show_bug.cgi?id=2006500
permissions-required

Sources

CVE List CVE-2026-0887
NVD CVE-2026-0887

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary