Vulnerability in Mozilla Firefox
CVE-2021-38509
Due to an unusual sequence of attacker-controlled events, a Javascript alert() dialog with arbitrary (although unstyled) contents could be displayed over top an uncontrolled webpage of the attacker's choosing. This vulnerability affects Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.016 (75.4th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 75th percentile — 75.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.016 · newest: 0.016 · change: +0.000
Affected products
- Mozilla Firefox — versions unspecified
- Mozilla Firefox Esr — versions unspecified
- Mozilla Firefox Esr
- Mozilla Thunderbird — versions unspecified
- Debian Linux — versions 9.0, 10.0, 11.0
Weakness classification (CWE)
References
- www.mozilla.org/security/advisories/mfsa2021-49/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2021-50/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2021-48/ (Vendor Advisory)
- bugzilla.mozilla.org/show_bug.cgi (Permissions Required, Issue Tracking, Vendor Advisory)
- www.debian.org/security/2021/dsa-5026 (vendor-advisory, Third Party Advisory)
- lists.debian.org/debian-lts-announce/2021/12/msg00030.html (mailing-list, Mailing List, Third Party Advisory)
- www.debian.org/security/2022/dsa-5034 (vendor-advisory, Mailing List, Third Party Advisory)
- lists.debian.org/debian-lts-announce/2022/01/msg00001.html (mailing-list, Mailing List, Third Party Advisory)
- security.gentoo.org/glsa/202202-03 (vendor-advisory, Third Party Advisory)
- security.gentoo.org/glsa/202208-14 (vendor-advisory, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-38509?
- CVE-2021-38509 is a medium-severity vulnerability in Mozilla Firefox, classified under Improper Restriction of Rendered UI Layers or Frames (Clickjacking). CVSS score: 4.3/10. Published 2021-12-08.
- How severe is CVE-2021-38509?
- Medium severity. CVSS v3 base score is 4.3 out of 10.