CVE-2026-0887
published 2026-01-13CVE-2026-0887: Clickjacking issue, information disclosure in the PDF Viewer component. This vulnerability was fixed in Firefox 147, Firefox ESR 140.7, Thunderbird 147, and…
PriorityP418medium4.3CVSS 3.1
AVNACLPRNUIRSUCLINAN
EPSS
0.28%
20.4th percentile
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.
Affected
12 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | firefox | < firefox 147.0-1 (sid) | firefox 147.0-1 (sid) |
| debian | firefox-esr | < firefox 147.0-1 (sid) | firefox 147.0-1 (sid) |
| debian | thunderbird | < firefox 147.0-1 (sid) | firefox 147.0-1 (sid) |
| mozilla | firefox | < 140.7.0 | 140.7.0 |
| mozilla | firefox | < 147.0 | 147.0 |
| mozilla | firefox | — | — |
| mozilla | thunderbird | < 140.7.0 | 140.7.0 |
| mozilla | thunderbird | < 147.0 | 147.0 |
| mozilla | thunderbird | >= 0 < 1:140.7.0esr-1~deb11u1 | 1:140.7.0esr-1~deb11u1 |
| mozilla | thunderbird | >= 0 < 1:140.7.0esr-1~deb12u1 | 1:140.7.0esr-1~deb12u1 |
| mozilla | thunderbird | >= 0 < 1:140.7.0esr-1~deb13u1 | 1:140.7.0esr-1~deb13u1 |
| mozilla | thunderbird | >= 0 < 1:140.7.0esr-1 | 1:140.7.0esr-1 |
CVSS provenance
nvdv3.14.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
osv4.3MEDIUM
vendor_debian4.3MEDIUM
vendor_redhat4.3MEDIUM
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Ubuntu
Thunderbird vulnerabilities
vendor_ubuntu·2026-02-02
CVE-2025-8031 Thunderbird vulnerabilities
Title: Thunderbird vulnerabilities
Summary: Several security issues were fixed in Thunderbird.
Multiple security issues were discovered in Thunderbird. If a user were
tricked into opening a specially crafted website in a browsing context,
an attacker could potentially exploit these to cause a denial of service,
obtain sensitive information, bypass security restrictions, cross-site
tracing, or execute arbitrary code.
Instructions: In general, a standard system update will make all the necessary changes.
Red Hat
firefox: thunderbird: Clickjacking issue, information disclosure in the PDF Viewer component
vendor_redhat·2026-01-13·CVSS 4.3
CVE-2026-0887 [MEDIUM] firefox: thunderbird: Clickjacking issue, information disclosure in the PDF Viewer component
firefox: thunderbird: Clickjacking issue, information disclosure in the PDF Viewer component
Clickjacking issue, information disclosure in the PDF Viewer component. This vulnerability affects Firefox < 147, Firefox ESR < 140.7, Thunderbird < 147, and Thunderbird < 140.7.
A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue:
Clickjacking issue, information disclosure in the PDF Viewer component
Statement: Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.
Package: rhel10/firefox-flatpak (Red Hat Enterprise Linux 10) - Affected
Package: rhel10/thunderbird-flatpak (Red Hat Enterprise Linux 10) - Affected
Package: firefox (Red Hat Enterprise Linux 6) - Out of
Debian
CVE-2026-0887: firefox - Clickjacking issue, information disclosure in the PDF Viewer component. This vul...
vendor_debian·2026·CVSS 4.3
CVE-2026-0887 [MEDIUM] CVE-2026-0887: firefox - Clickjacking issue, information disclosure in the PDF Viewer component. This vul...
Clickjacking issue, information disclosure in the PDF Viewer component. This vulnerability affects Firefox < 147, Firefox ESR < 140.7, Thunderbird < 147, and Thunderbird < 140.7.
Scope: local
sid: resolved (fixed in 147.0-1)
Mozilla
Mozilla Foundation Security Advisory 2026-05: CVE-2026-0887
vendor_mozilla·CVSS 4.3
CVE-2026-0887 [MEDIUM] Mozilla Foundation Security Advisory 2026-05: CVE-2026-0887
Mozilla Foundation Security Advisory 2026-05
CVE: CVE-2026-0887
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140.7
Mozilla
Mozilla Foundation Security Advisory 2026-03: CVE-2026-0887
vendor_mozilla·CVSS 4.3
CVE-2026-0887 [MEDIUM] Mozilla Foundation Security Advisory 2026-03: CVE-2026-0887
Mozilla Foundation Security Advisory 2026-03
CVE: CVE-2026-0887
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 140.7
Mozilla
Mozilla Foundation Security Advisory 2026-01: CVE-2026-0887
vendor_mozilla·CVSS 4.3
CVE-2026-0887 [MEDIUM] Mozilla Foundation Security Advisory 2026-01: CVE-2026-0887
Mozilla Foundation Security Advisory 2026-01
CVE: CVE-2026-0887
Product: Firefox
Impact: moderate
Fixed in: Firefox 147
Mozilla
Mozilla Foundation Security Advisory 2026-04: CVE-2026-0887
vendor_mozilla·CVSS 4.3
CVE-2026-0887 [MEDIUM] Mozilla Foundation Security Advisory 2026-04: CVE-2026-0887
Mozilla Foundation Security Advisory 2026-04
CVE: CVE-2026-0887
Product: Thunderbird
Impact: moderate
Fixed in: Thunderbird 147
OSV
CVE-2026-0887: Clickjacking issue, information disclosure in the PDF Viewer component
osv·2026-01-13·CVSS 4.3
CVE-2026-0887 [MEDIUM] CVE-2026-0887: Clickjacking issue, information disclosure in the PDF Viewer component
Clickjacking issue, information disclosure in the PDF Viewer component. This vulnerability affects Firefox < 147, Firefox ESR < 140.7, Thunderbird < 147, and Thunderbird < 140.7.
GHSA
GHSA-96f5-9x27-7hhh: Clickjacking issue, information disclosure in the PDF Viewer component
ghsa_unreviewed·2026-01-13
CVE-2026-0887 [MEDIUM] CWE-497 GHSA-96f5-9x27-7hhh: Clickjacking issue, information disclosure in the PDF Viewer component
Clickjacking issue, information disclosure in the PDF Viewer component. This vulnerability affects Firefox < 147 and Firefox ESR < 140.7.
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-0887 firefox: thunderbird: Clickjacking issue, information disclosure in the PDF Viewer component
bugzilla·2026-01-13·CVSS 4.3
CVE-2026-0887 [MEDIUM] CVE-2026-0887 firefox: thunderbird: Clickjacking issue, information disclosure in the PDF Viewer component
CVE-2026-0887 firefox: thunderbird: Clickjacking issue, information disclosure in the PDF Viewer component
Clickjacking issue, information disclosure in the PDF Viewer component. This vulnerability affects Firefox < 147 and Firefox ESR < 140.7.
Discussion:
This issue has been addressed in the following products:
Red Hat Enterprise Linux 8
Via RHSA-2026:0667 https://access.redhat.com/errata/RHSA-2026:0667
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux 9
Via RHSA-2026:0694 https://access.redhat.com/errata/RHSA-2026:0694
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux 9
Via RHSA-2026:0924 https://access.redhat.com/errata/RHSA-2026:0924
---
This issue has been addressed in the following products:
Red H
Wiz
CVE-2026-0887 Impact, Exploitability, and Mitigation Steps | Wiz
blogs_wiz·CVSS 4.3
CVE-2026-0887 [MEDIUM] CVE-2026-0887 Impact, Exploitability, and Mitigation Steps | Wiz
## CVE-2026-0887 :
NixOS vulnerability analysis and mitigation
Clickjacking issue, information disclosure in the PDF Viewer component. This vulnerability affects Firefox < 147, Firefox ESR < 140.7, Thunderbird < 147, and Thunderbird < 140.7.
Source : NVD
## 4.3
Score
Published January 13, 2026
Severity MEDIUM
CNA Score 4.3
Affected Technologies
NixOS
Mozilla Firefox
Has Public Exploit No
Has CISA KEV Exploit No
CISA KEV Release Date N/A
CISA KEV Due Date N/A
Exploitation Probability Percentile (EPSS) 2.7
Exploitation Probability (EPSS) N/A
Affected packages and libraries
rhel10::firefox-flatpak.src
firefox-debuginfo
Sources
AlmaLinux 8 Severity HIGH Has Fix Added at: Feb 11, 2026
AlmaLinux 9 Severity HIGH Has Fix Added at: Jan 20, 2026
Debian 11, 12, 13, 14 Severi
2026-01-13
Published