critical
CVE-2021-38503
Mozilla: iframe sandbox rules did not apply to XSLT stylesheets
In the Trivy database since at least 24 Oct 2026, 07:11 UTCWhen it arrived before that build is not recorded.
Severity by source
NVD10.0CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Red Hat10.0CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Trivy's own label is CRITICAL. Rated critical by NVD. Rated lower by Red Hat (high), AlmaLinux (high), Amazon (high), Oracle (high), Rocky Linux (high), Ubuntu (medium).
Description
The iframe sandbox rules were not correctly applied to XSLT stylesheets, allowing an iframe to bypass restrictions such as executing scripts or navigating the top-level frame. This vulnerability affects Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.
Affected packages and fixed versions
| Source | Package | Fixed in |
|---|---|---|
| alma 8 | firefox, thunderbird | 91.3.0-1.el8_4.alma and 1 more |
| alpine 3.15 | firefox, firefox-esr | 94.0-r0 and 1 more |
| alpine 3.16 | firefox, firefox-esr, thunderbird | 94.0-r0 and 2 more |
| alpine 3.17 | firefox, firefox-esr, thunderbird | 94.0-r0 and 2 more |
| alpine 3.18 | firefox, firefox-esr, thunderbird | 94.0-r0 and 2 more |
| alpine 3.19 | firefox, firefox-esr, thunderbird | 94.0-r0 and 2 more |
| alpine 3.20 | firefox, firefox-esr, thunderbird | 94.0-r0 and 2 more |
| alpine 3.21 | firefox, firefox-esr, librewolf and 1 more | 94.0-r0 and 2 more |
| alpine 3.22 | firefox, firefox-esr, librewolf and 1 more | 94.0-r0 and 2 more |
| alpine 3.23 | firefox, firefox-esr, librewolf and 1 more | 94.0-r0 and 2 more |
| alpine 3.24 | librewolf | 94.0-r0 |
| alpine edge | librewolf | 94.0-r0 |
Show all 73 entries from 33 sources
| Source | Package | Fixed in |
|---|---|---|
| alma 8 | firefox | 91.3.0-1.el8_4.alma |
| alma 8 | thunderbird | 91.3.0-2.el8_4.alma |
| alpine 3.15 | firefox | 94.0-r0 |
| alpine 3.15 | firefox-esr | 91.3.0-r0 |
| alpine 3.16 | firefox | 94.0-r0 |
| alpine 3.16 | firefox-esr | 91.3.0-r0 |
| alpine 3.16 | thunderbird | 91.3.2-r0 |
| alpine 3.17 | firefox | 94.0-r0 |
| alpine 3.17 | firefox-esr | 91.3.0-r0 |
| alpine 3.17 | thunderbird | 91.3.2-r0 |
| alpine 3.18 | firefox | 94.0-r0 |
| alpine 3.18 | firefox-esr | 91.3.0-r0 |
| alpine 3.18 | thunderbird | 91.3.2-r0 |
| alpine 3.19 | firefox | 94.0-r0 |
| alpine 3.19 | firefox-esr | 91.3.0-r0 |
| alpine 3.19 | thunderbird | 91.3.2-r0 |
| alpine 3.20 | firefox | 94.0-r0 |
| alpine 3.20 | firefox-esr | 91.3.0-r0 |
| alpine 3.20 | thunderbird | 91.3.2-r0 |
| alpine 3.21 | firefox | 94.0-r0 |
| alpine 3.21 | firefox-esr | 91.3.0-r0 |
| alpine 3.21 | librewolf | 94.0-r0 |
| alpine 3.21 | thunderbird | 91.3.2-r0 |
| alpine 3.22 | firefox | 94.0-r0 |
| alpine 3.22 | firefox-esr | 91.3.0-r0 |
| alpine 3.22 | librewolf | 94.0-r0 |
| alpine 3.22 | thunderbird | 91.3.2-r0 |
| alpine 3.23 | firefox | 94.0-r0 |
| alpine 3.23 | firefox-esr | 91.3.0-r0 |
| alpine 3.23 | librewolf | 94.0-r0 |
| alpine 3.23 | thunderbird | 91.3.2-r0 |
| alpine 3.24 | librewolf | 94.0-r0 |
| alpine edge | librewolf | 94.0-r0 |
| amazon linux 2 | thunderbird | 91.6.0-1.amzn2.0.1 |
| amazon linux 2 | thunderbird-debuginfo | 91.6.0-1.amzn2.0.1 |
| debian 10 | thunderbird | 1:91.4.1-1~deb10u1 |
| debian 11 | firefox-esr | 91.4.1esr-1~deb11u1 |
| debian 11 | thunderbird | 1:91.4.1-1~deb11u1 |
| debian 12 | firefox-esr | 91.3.0esr-1 |
| debian 12 | thunderbird | 1:91.3.0-1 |
| debian 13 | firefox-esr | 91.3.0esr-1 |
| debian 13 | thunderbird | 1:91.3.0-1 |
| debian 14 | firefox-esr | 91.3.0esr-1 |
| debian 14 | thunderbird | 1:91.3.0-1 |
| debian 9 | firefox-esr | 91.4.1esr-1~deb9u1 |
| debian 9 | thunderbird | 1:91.4.1-1~deb9u1 |
| echo | firefox-esr | 91.3.0esr-1 |
| echo | thunderbird | 1:91.3.0-1 |
| Oracle Linux 7 | firefox | 91.3.0-1.0.1.el7_9 |
| Oracle Linux 7 | thunderbird | 91.3.0-2.0.1.el7_9 |
| Oracle Linux 8 | firefox | 91.3.0-1.0.1.el8_4 |
| Oracle Linux 8 | thunderbird | 91.3.0-2.0.1.el8_4 |
| Red Hat | firefox | no fix listed |
| Red Hat | thunderbird | no fix listed |
| rocky 8 | firefox | 91.3.0-1.el8_4 |
| rocky 8 | thunderbird | 91.3.0-2.el8 |
| ubuntu 18.04 | firefox | 94.0+build3-0ubuntu0.18.04.1 |
| ubuntu 18.04 | thunderbird | 1:91.5.0+build1-0ubuntu0.18.04.1 |
| ubuntu 20.04 | firefox | 94.0+build3-0ubuntu0.20.04.1 |
| ubuntu 20.04 | thunderbird | 1:91.5.0+build1-0ubuntu0.20.04.1 |
| ubuntu 21.04 | firefox | 94.0+build3-0ubuntu0.21.04.1 |
| ubuntu 21.10 | firefox | 94.0+build3-0ubuntu0.21.10.1 |
| ubuntu 21.10 | thunderbird | 1:91.3.1+build1-0ubuntu0.21.10.1 |
| ubuntu 22.04 | firefox | 94.0+build3-0ubuntu1 |
| ubuntu 22.04 | thunderbird | 1:91.3.1+build1-0ubuntu1 |
| ubuntu 22.10 | firefox | 94.0+build3-0ubuntu1 |
| ubuntu 22.10 | thunderbird | 1:91.3.1+build1-0ubuntu1 |
| ubuntu 23.04 | firefox | 94.0+build3-0ubuntu1 |
| ubuntu 23.04 | thunderbird | 1:91.3.1+build1-0ubuntu1 |
| ubuntu 23.10 | firefox | 94.0+build3-0ubuntu1 |
| ubuntu 23.10 | thunderbird | 1:91.3.1+build1-0ubuntu1 |
| ubuntu 24.04 | firefox | 94.0+build3-0ubuntu1 |
| ubuntu 24.04 | thunderbird | 1:91.3.1+build1-0ubuntu1 |
References
- https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-38503.json
- https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-38504.json
- https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-38506.json
- https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-38507.json
- https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-38508.json
- https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-38509.json
- https://access.redhat.com/security/cve/CVE-2021-38503
- https://bugzilla.mozilla.org/show_bug.cgi?id=1729517
All 26 references
- https://linux.oracle.com/cve/CVE-2021-38503.html
- https://linux.oracle.com/errata/ELSA-2021-4134.html
- https://lists.debian.org/debian-lts-announce/2021/12/msg00030.html
- https://lists.debian.org/debian-lts-announce/2022/01/msg00001.html
- https://nvd.nist.gov/vuln/detail/CVE-2021-38503
- https://security.gentoo.org/glsa/202202-03
- https://security.gentoo.org/glsa/202208-14
- https://ubuntu.com/security/notices/USN-5131-1
- https://ubuntu.com/security/notices/USN-5152-1
- https://ubuntu.com/security/notices/USN-5248-1
- https://www.cve.org/CVERecord?id=CVE-2021-38503
- https://www.debian.org/security/2021/dsa-5026
- https://www.debian.org/security/2022/dsa-5034
- https://www.mozilla.org/en-US/security/advisories/mfsa2021-48/#CVE-2021-38503
- https://www.mozilla.org/en-US/security/advisories/mfsa2021-49/#CVE-2021-38503
- https://www.mozilla.org/security/advisories/mfsa2021-48/
- https://www.mozilla.org/security/advisories/mfsa2021-49/
- https://www.mozilla.org/security/advisories/mfsa2021-50/