CVE-2026-0818
CSS-based exfiltration of the content from partially encrypted emails when allowing remote content
CVE-2026-0818 is fixed in 139 products on 2 platforms, first by Mozilla Thunderbird (af) 147.0.1, released January 28, 2026. It is not reported as exploited. Patch Radar priority: Routine.
RoutineFixed on 2 platforms
CVSS
4.3
Medium
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0018
7th percentile
When a user explicitly requested Thunderbird to decrypt an inline OpenPGP message that was embedded in a text section of an email that was formatted and styled with HTML and CSS, then the decrypted contents were rendered in a context in which the CSS styles from the outer messages were active. If the user had additionally allowed loading of the remote content referenced by the outer email message, and the email was crafted by the sender using a combination of CSS rules and fonts and animations, then it was possible to extract the secret contents of the email. This vulnerability was fixed in Thunderbird 147.0.1 and Thunderbird 140.7.1.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Windows apps | |||
| Mozilla Thunderbird (af) | 147.0.1 | Mozilla Thunderbird (af) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (ar) | 147.0.1 | Mozilla Thunderbird (ar) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (ast) | 147.0.1 | Mozilla Thunderbird (ast) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (be) | 147.0.1 | Mozilla Thunderbird (be) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (bg) | 147.0.1 | Mozilla Thunderbird (bg) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (br) | 147.0.1 | Mozilla Thunderbird (br) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (ca) | 147.0.1 | Mozilla Thunderbird (ca) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (cak) | 147.0.1 | Mozilla Thunderbird (cak) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (cs) | 147.0.1 | Mozilla Thunderbird (cs) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (cy) | 147.0.1 | Mozilla Thunderbird (cy) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (da) | 147.0.1 | Mozilla Thunderbird (da) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (de) | 147.0.1 | Mozilla Thunderbird (de) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (dsb) | 147.0.1 | Mozilla Thunderbird (dsb) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (el) | 147.0.1 | Mozilla Thunderbird (el) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (en-CA) | 147.0.1 | Mozilla Thunderbird (en-CA) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (en-GB) | 147.0.1 | Mozilla Thunderbird (en-GB) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (en-US) | 147.0.1 | Mozilla Thunderbird (en-US) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (es-AR) | 147.0.1 | Mozilla Thunderbird (es-AR) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (es-ES) | 147.0.1 | Mozilla Thunderbird (es-ES) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (es-MX) | 147.0.1 | Mozilla Thunderbird (es-MX) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (et) | 147.0.1 | Mozilla Thunderbird (et) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (eu) | 147.0.1 | Mozilla Thunderbird (eu) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (fi) | 147.0.1 | Mozilla Thunderbird (fi) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (fr) | 147.0.1 | Mozilla Thunderbird (fr) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (fy-NL) | 147.0.1 | Mozilla Thunderbird (fy-NL) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (ga-IE) | 147.0.1 | Mozilla Thunderbird (ga-IE) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (gd) | 147.0.1 | Mozilla Thunderbird (gd) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (gl) | 147.0.1 | Mozilla Thunderbird (gl) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (he) | 147.0.1 | Mozilla Thunderbird (he) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (hr) | 147.0.1 | Mozilla Thunderbird (hr) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (hsb) | 147.0.1 | Mozilla Thunderbird (hsb) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (hu) | 147.0.1 | Mozilla Thunderbird (hu) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (hy-AM) | 147.0.1 | Mozilla Thunderbird (hy-AM) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (id) | 147.0.1 | Mozilla Thunderbird (id) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (is) | 147.0.1 | Mozilla Thunderbird (is) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (it) | 147.0.1 | Mozilla Thunderbird (it) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (ja) | 147.0.1 | Mozilla Thunderbird (ja) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (ka) | 147.0.1 | Mozilla Thunderbird (ka) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (kab) | 147.0.1 | Mozilla Thunderbird (kab) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (kk) | 147.0.1 | Mozilla Thunderbird (kk) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (ko) | 147.0.1 | Mozilla Thunderbird (ko) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (lt) | 147.0.1 | Mozilla Thunderbird (lt) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (lv) | 147.0.1 | Mozilla Thunderbird (lv) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (ms) | 147.0.1 | Mozilla Thunderbird (ms) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (nb-NO) | 147.0.1 | Mozilla Thunderbird (nb-NO) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (nl) | 147.0.1 | Mozilla Thunderbird (nl) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (nn-NO) | 147.0.1 | Mozilla Thunderbird (nn-NO) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (pa-IN) | 147.0.1 | Mozilla Thunderbird (pa-IN) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (pl) | 147.0.1 | Mozilla Thunderbird (pl) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (pt-BR) | 147.0.1 | Mozilla Thunderbird (pt-BR) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (pt-PT) | 147.0.1 | Mozilla Thunderbird (pt-PT) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (rm) | 147.0.1 | Mozilla Thunderbird (rm) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (ro) | 147.0.1 | Mozilla Thunderbird (ro) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (ru) | 147.0.1 | Mozilla Thunderbird (ru) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (sk) | 147.0.1 | Mozilla Thunderbird (sk) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (sl) | 147.0.1 | Mozilla Thunderbird (sl) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (sq) | 147.0.1 | Mozilla Thunderbird (sq) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (sr) | 147.0.1 | Mozilla Thunderbird (sr) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (sv-SE) | 147.0.1 | Mozilla Thunderbird (sv-SE) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (th) | 147.0.1 | Mozilla Thunderbird (th) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (tr) | 147.0.1 | Mozilla Thunderbird (tr) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (uk) | 147.0.1 | Mozilla Thunderbird (uk) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (uz) | 147.0.1 | Mozilla Thunderbird (uz) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (vi) | 147.0.1 | Mozilla Thunderbird (vi) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (zh-CN) | 147.0.1 | Mozilla Thunderbird (zh-CN) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird (zh-TW) | 147.0.1 | Mozilla Thunderbird (zh-TW) 147.0.1 | Jan 28, 2026 |
| Mozilla Thunderbird ESR (af) | 153.0.1 | Mozilla Thunderbird ESR (af) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (ar) | 153.0.1 | Mozilla Thunderbird ESR (ar) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (ast) | 153.0.1 | Mozilla Thunderbird ESR (ast) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (be) | 153.0.1 | Mozilla Thunderbird ESR (be) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (bg) | 153.0.1 | Mozilla Thunderbird ESR (bg) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (br) | 153.0.1 | Mozilla Thunderbird ESR (br) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (ca) | 153.0.1 | Mozilla Thunderbird ESR (ca) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (cak) | 153.0.1 | Mozilla Thunderbird ESR (cak) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (cs) | 153.0.1 | Mozilla Thunderbird ESR (cs) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (cy) | 153.0.1 | Mozilla Thunderbird ESR (cy) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (da) | 153.0.1 | Mozilla Thunderbird ESR (da) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (de) | 153.0.1 | Mozilla Thunderbird ESR (de) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (dsb) | 153.0.1 | Mozilla Thunderbird ESR (dsb) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (el) | 153.0.1 | Mozilla Thunderbird ESR (el) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (en-CA) | 153.0.1 | Mozilla Thunderbird ESR (en-CA) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (en-GB) | 153.0.1 | Mozilla Thunderbird ESR (en-GB) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (en-US) | 153.0.1 | Mozilla Thunderbird ESR (en-US) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (es-AR) | 153.0.1 | Mozilla Thunderbird ESR (es-AR) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (es-ES) | 153.0.1 | Mozilla Thunderbird ESR (es-ES) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (es-MX) | 153.0.1 | Mozilla Thunderbird ESR (es-MX) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (et) | 153.0.1 | Mozilla Thunderbird ESR (et) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (eu) | 153.0.1 | Mozilla Thunderbird ESR (eu) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (fi) | 153.0.1 | Mozilla Thunderbird ESR (fi) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (fr) | 153.0.1 | Mozilla Thunderbird ESR (fr) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (fy-NL) | 153.0.1 | Mozilla Thunderbird ESR (fy-NL) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (ga-IE) | 153.0.1 | Mozilla Thunderbird ESR (ga-IE) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (gd) | 153.0.1 | Mozilla Thunderbird ESR (gd) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (gl) | 153.0.1 | Mozilla Thunderbird ESR (gl) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (he) | 153.0.1 | Mozilla Thunderbird ESR (he) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (hr) | 153.0.1 | Mozilla Thunderbird ESR (hr) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (hsb) | 153.0.1 | Mozilla Thunderbird ESR (hsb) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (hu) | 153.0.1 | Mozilla Thunderbird ESR (hu) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (hy-AM) | 153.0.1 | Mozilla Thunderbird ESR (hy-AM) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (id) | 153.0.1 | Mozilla Thunderbird ESR (id) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (is) | 153.0.1 | Mozilla Thunderbird ESR (is) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (it) | 153.0.1 | Mozilla Thunderbird ESR (it) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (ja) | 153.0.1 | Mozilla Thunderbird ESR (ja) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (ka) | 153.0.1 | Mozilla Thunderbird ESR (ka) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (kab) | 153.0.1 | Mozilla Thunderbird ESR (kab) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (kk) | 153.0.1 | Mozilla Thunderbird ESR (kk) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (ko) | 153.0.1 | Mozilla Thunderbird ESR (ko) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (lt) | 153.0.1 | Mozilla Thunderbird ESR (lt) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (lv) | 153.0.1 | Mozilla Thunderbird ESR (lv) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (ms) | 153.0.1 | Mozilla Thunderbird ESR (ms) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (nb-NO) | 153.0.1 | Mozilla Thunderbird ESR (nb-NO) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (nl) | 153.0.1 | Mozilla Thunderbird ESR (nl) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (nn-NO) | 153.0.1 | Mozilla Thunderbird ESR (nn-NO) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (pa-IN) | 153.0.1 | Mozilla Thunderbird ESR (pa-IN) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (pl) | 153.0.1 | Mozilla Thunderbird ESR (pl) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (pt-BR) | 153.0.1 | Mozilla Thunderbird ESR (pt-BR) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (pt-PT) | 153.0.1 | Mozilla Thunderbird ESR (pt-PT) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (rm) | 153.0.1 | Mozilla Thunderbird ESR (rm) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (ro) | 153.0.1 | Mozilla Thunderbird ESR (ro) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (ru) | 153.0.1 | Mozilla Thunderbird ESR (ru) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (sk) | 153.0.1 | Mozilla Thunderbird ESR (sk) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (sl) | 153.0.1 | Mozilla Thunderbird ESR (sl) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (sq) | 153.0.1 | Mozilla Thunderbird ESR (sq) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (sr) | 153.0.1 | Mozilla Thunderbird ESR (sr) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (sv-SE) | 153.0.1 | Mozilla Thunderbird ESR (sv-SE) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (th) | 153.0.1 | Mozilla Thunderbird ESR (th) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (tr) | 153.0.1 | Mozilla Thunderbird ESR (tr) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (uk) | 153.0.1 | Mozilla Thunderbird ESR (uk) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (uz) | 153.0.1 | Mozilla Thunderbird ESR (uz) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (vi) | 153.0.1 | Mozilla Thunderbird ESR (vi) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (zh-CN) | 153.0.1 | Mozilla Thunderbird ESR (zh-CN) 153.0.1 | Jul 23, 2026 |
| Mozilla Thunderbird ESR (zh-TW) | 153.0.1 | Mozilla Thunderbird ESR (zh-TW) 153.0.1 | Jul 23, 2026 |
| Linux | |||
| MozillaThunderbird · opensuse-leap 15.6 | 140.7.1-150200.8.254.1 | SUSE-SU-2026:0388-1 | Feb 5, 2026 |
| MozillaThunderbird · opensuse-leap 16.0 | 140.8.1-bp160.1.1 | OPENSUSE-SU-2026:20391-1 | Mar 18, 2026 |
| MozillaThunderbird · sles 15.7 | 140.7.1-150200.8.254.1 | SUSE-SU-2026:0388-1 | Feb 5, 2026 |
| thunderbird · Debian 11.6 (bullseye) | 1:140.7.1esr-1~deb11u1 | DLA-4466-1 | Feb 4, 2026 |
| thunderbird · Debian 12.15 (bookworm) | 1:140.7.1esr-1~deb12u1 | DSA-6118-1 | Feb 3, 2026 |
| thunderbird · Debian 13.5 (trixie) | 1:140.7.1esr-1~deb13u1 | DSA-6118-1 | Feb 3, 2026 |
| thunderbird · Debian 14 | 1:140.7.1esr-1 | DEBIAN-CVE-2026-0818 | Jan 28, 2026 |
| thunderbird · Ubuntu 22.04.1 LTS (jammy) | 1:140.7.1+build1-0ubuntu0.22.04.1 | thunderbird 1:140.7.1+build1-0ubuntu0.22.04.1 | Jan 28, 2026 |
| thunderbird-gnome-support · Ubuntu 22.04.1 LTS (jammy) | 1:140.7.1+build1-0ubuntu0.22.04.1 | thunderbird-gnome-support 1:140.7.1+build1-0ubuntu0.22.04.1 | Jan 28, 2026 |
| thunderbird-mozsymbols · Ubuntu 22.04.1 LTS (jammy) | 1:140.7.1+build1-0ubuntu0.22.04.1 | thunderbird-mozsymbols 1:140.7.1+build1-0ubuntu0.22.04.1 | Jan 28, 2026 |
| xul-ext-calendar-timezones · Ubuntu 22.04.1 LTS (jammy) | 1:140.7.1+build1-0ubuntu0.22.04.1 | xul-ext-calendar-timezones 1:140.7.1+build1-0ubuntu0.22.04.1 | Jan 28, 2026 |
| xul-ext-gdata-provider · Ubuntu 22.04.1 LTS (jammy) | 1:140.7.1+build1-0ubuntu0.22.04.1 | xul-ext-gdata-provider 1:140.7.1+build1-0ubuntu0.22.04.1 | Jan 28, 2026 |
| xul-ext-lightning · Ubuntu 22.04.1 LTS (jammy) | 1:140.7.1+build1-0ubuntu0.22.04.1 | xul-ext-lightning 1:140.7.1+build1-0ubuntu0.22.04.1 | Jan 28, 2026 |
Patch Radar data is free to use with attribution. Terms and how to credit it.
Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.