CVE-2026-103500
Heap buffer overflow opening large email
CVE-2026-103500 is fixed in 135 products on 3 platforms, first by Mozilla Thunderbird 157.0, released September 28, 2026. It is not reported as exploited. Patch Radar priority: Routine.
RoutineFixed on 3 platforms
CVSS
6.1
medium
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0028
20th percentile
An attacker could cause a heap buffer overflow by getting a user to open an email that is greater than or equal to 2GB in size. This vulnerability was fixed in Thunderbird 157, Thunderbird 140.17, and Thunderbird 153.4.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Windows apps | |||
| Mozilla Thunderbird (af) | 157.0 | Mozilla Thunderbird (af) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (ar) | 157.0 | Mozilla Thunderbird (ar) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (ast) | 157.0 | Mozilla Thunderbird (ast) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (be) | 157.0 | Mozilla Thunderbird (be) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (bg) | 157.0 | Mozilla Thunderbird (bg) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (br) | 157.0 | Mozilla Thunderbird (br) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (ca) | 157.0 | Mozilla Thunderbird (ca) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (cak) | 157.0 | Mozilla Thunderbird (cak) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (cs) | 157.0 | Mozilla Thunderbird (cs) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (cy) | 157.0 | Mozilla Thunderbird (cy) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (da) | 157.0 | Mozilla Thunderbird (da) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (de) | 157.0 | Mozilla Thunderbird (de) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (dsb) | 157.0 | Mozilla Thunderbird (dsb) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (el) | 157.0 | Mozilla Thunderbird (el) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (en-CA) | 157.0 | Mozilla Thunderbird (en-CA) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (en-GB) | 157.0 | Mozilla Thunderbird (en-GB) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (en-US) | 157.0 | Mozilla Thunderbird (en-US) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (es-AR) | 157.0 | Mozilla Thunderbird (es-AR) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (es-ES) | 157.0 | Mozilla Thunderbird (es-ES) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (es-MX) | 157.0 | Mozilla Thunderbird (es-MX) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (et) | 157.0 | Mozilla Thunderbird (et) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (eu) | 157.0 | Mozilla Thunderbird (eu) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (fi) | 157.0 | Mozilla Thunderbird (fi) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (fr) | 157.0 | Mozilla Thunderbird (fr) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (fy-NL) | 157.0 | Mozilla Thunderbird (fy-NL) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (ga-IE) | 157.0 | Mozilla Thunderbird (ga-IE) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (gd) | 157.0 | Mozilla Thunderbird (gd) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (gl) | 157.0 | Mozilla Thunderbird (gl) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (he) | 157.0 | Mozilla Thunderbird (he) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (hr) | 157.0 | Mozilla Thunderbird (hr) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (hsb) | 157.0 | Mozilla Thunderbird (hsb) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (hu) | 157.0 | Mozilla Thunderbird (hu) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (hy-AM) | 157.0 | Mozilla Thunderbird (hy-AM) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (id) | 157.0 | Mozilla Thunderbird (id) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (is) | 157.0 | Mozilla Thunderbird (is) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (it) | 157.0 | Mozilla Thunderbird (it) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (ja) | 157.0 | Mozilla Thunderbird (ja) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (ka) | 157.0 | Mozilla Thunderbird (ka) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (kab) | 157.0 | Mozilla Thunderbird (kab) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (kk) | 157.0 | Mozilla Thunderbird (kk) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (ko) | 157.0 | Mozilla Thunderbird (ko) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (lt) | 157.0 | Mozilla Thunderbird (lt) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (lv) | 157.0 | Mozilla Thunderbird (lv) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (ms) | 157.0 | Mozilla Thunderbird (ms) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (nb-NO) | 157.0 | Mozilla Thunderbird (nb-NO) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (nl) | 157.0 | Mozilla Thunderbird (nl) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (nn-NO) | 157.0 | Mozilla Thunderbird (nn-NO) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (pa-IN) | 157.0 | Mozilla Thunderbird (pa-IN) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (pl) | 157.0 | Mozilla Thunderbird (pl) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (pt-BR) | 157.0 | Mozilla Thunderbird (pt-BR) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (pt-PT) | 157.0 | Mozilla Thunderbird (pt-PT) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (rm) | 157.0 | Mozilla Thunderbird (rm) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (ro) | 157.0 | Mozilla Thunderbird (ro) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (ru) | 157.0 | Mozilla Thunderbird (ru) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (sk) | 157.0 | Mozilla Thunderbird (sk) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (sl) | 157.0 | Mozilla Thunderbird (sl) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (sq) | 157.0 | Mozilla Thunderbird (sq) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (sr) | 157.0 | Mozilla Thunderbird (sr) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (sv-SE) | 157.0 | Mozilla Thunderbird (sv-SE) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (th) | 157.0 | Mozilla Thunderbird (th) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (tr) | 157.0 | Mozilla Thunderbird (tr) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (uk) | 157.0 | Mozilla Thunderbird (uk) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (uz) | 157.0 | Mozilla Thunderbird (uz) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (vi) | 157.0 | Mozilla Thunderbird (vi) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (zh-CN) | 157.0 | Mozilla Thunderbird (zh-CN) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird (zh-TW) | 157.0 | Mozilla Thunderbird (zh-TW) 157.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (af) | 153.4.0 | Mozilla Thunderbird ESR (af) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (ar) | 153.4.0 | Mozilla Thunderbird ESR (ar) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (ast) | 153.4.0 | Mozilla Thunderbird ESR (ast) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (be) | 153.4.0 | Mozilla Thunderbird ESR (be) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (bg) | 153.4.0 | Mozilla Thunderbird ESR (bg) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (br) | 153.4.0 | Mozilla Thunderbird ESR (br) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (ca) | 153.4.0 | Mozilla Thunderbird ESR (ca) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (cak) | 153.4.0 | Mozilla Thunderbird ESR (cak) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (cs) | 153.4.0 | Mozilla Thunderbird ESR (cs) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (cy) | 153.4.0 | Mozilla Thunderbird ESR (cy) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (da) | 153.4.0 | Mozilla Thunderbird ESR (da) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (de) | 153.4.0 | Mozilla Thunderbird ESR (de) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (dsb) | 153.4.0 | Mozilla Thunderbird ESR (dsb) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (el) | 153.4.0 | Mozilla Thunderbird ESR (el) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (en-CA) | 153.4.0 | Mozilla Thunderbird ESR (en-CA) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (en-GB) | 153.4.0 | Mozilla Thunderbird ESR (en-GB) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (en-US) | 153.4.0 | Mozilla Thunderbird ESR (en-US) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (es-AR) | 153.4.0 | Mozilla Thunderbird ESR (es-AR) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (es-ES) | 153.4.0 | Mozilla Thunderbird ESR (es-ES) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (es-MX) | 153.4.0 | Mozilla Thunderbird ESR (es-MX) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (et) | 153.4.0 | Mozilla Thunderbird ESR (et) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (eu) | 153.4.0 | Mozilla Thunderbird ESR (eu) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (fi) | 153.4.0 | Mozilla Thunderbird ESR (fi) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (fr) | 153.4.0 | Mozilla Thunderbird ESR (fr) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (fy-NL) | 153.4.0 | Mozilla Thunderbird ESR (fy-NL) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (ga-IE) | 153.4.0 | Mozilla Thunderbird ESR (ga-IE) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (gd) | 153.4.0 | Mozilla Thunderbird ESR (gd) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (gl) | 153.4.0 | Mozilla Thunderbird ESR (gl) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (he) | 153.4.0 | Mozilla Thunderbird ESR (he) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (hr) | 153.4.0 | Mozilla Thunderbird ESR (hr) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (hsb) | 153.4.0 | Mozilla Thunderbird ESR (hsb) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (hu) | 153.4.0 | Mozilla Thunderbird ESR (hu) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (hy-AM) | 153.4.0 | Mozilla Thunderbird ESR (hy-AM) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (id) | 153.4.0 | Mozilla Thunderbird ESR (id) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (is) | 153.4.0 | Mozilla Thunderbird ESR (is) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (it) | 153.4.0 | Mozilla Thunderbird ESR (it) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (ja) | 153.4.0 | Mozilla Thunderbird ESR (ja) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (ka) | 153.4.0 | Mozilla Thunderbird ESR (ka) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (kab) | 153.4.0 | Mozilla Thunderbird ESR (kab) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (kk) | 153.4.0 | Mozilla Thunderbird ESR (kk) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (ko) | 153.4.0 | Mozilla Thunderbird ESR (ko) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (lt) | 153.4.0 | Mozilla Thunderbird ESR (lt) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (lv) | 153.4.0 | Mozilla Thunderbird ESR (lv) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (ms) | 153.4.0 | Mozilla Thunderbird ESR (ms) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (nb-NO) | 153.4.0 | Mozilla Thunderbird ESR (nb-NO) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (nl) | 153.4.0 | Mozilla Thunderbird ESR (nl) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (nn-NO) | 153.4.0 | Mozilla Thunderbird ESR (nn-NO) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (pa-IN) | 153.4.0 | Mozilla Thunderbird ESR (pa-IN) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (pl) | 153.4.0 | Mozilla Thunderbird ESR (pl) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (pt-BR) | 153.4.0 | Mozilla Thunderbird ESR (pt-BR) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (pt-PT) | 153.4.0 | Mozilla Thunderbird ESR (pt-PT) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (rm) | 153.4.0 | Mozilla Thunderbird ESR (rm) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (ro) | 153.4.0 | Mozilla Thunderbird ESR (ro) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (ru) | 153.4.0 | Mozilla Thunderbird ESR (ru) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (sk) | 153.4.0 | Mozilla Thunderbird ESR (sk) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (sl) | 153.4.0 | Mozilla Thunderbird ESR (sl) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (sq) | 153.4.0 | Mozilla Thunderbird ESR (sq) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (sr) | 153.4.0 | Mozilla Thunderbird ESR (sr) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (sv-SE) | 153.4.0 | Mozilla Thunderbird ESR (sv-SE) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (th) | 153.4.0 | Mozilla Thunderbird ESR (th) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (tr) | 153.4.0 | Mozilla Thunderbird ESR (tr) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (uk) | 153.4.0 | Mozilla Thunderbird ESR (uk) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (uz) | 153.4.0 | Mozilla Thunderbird ESR (uz) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (vi) | 153.4.0 | Mozilla Thunderbird ESR (vi) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (zh-CN) | 153.4.0 | Mozilla Thunderbird ESR (zh-CN) 153.4.0 | Sep 30, 2026 |
| Mozilla Thunderbird ESR (zh-TW) | 153.4.0 | Mozilla Thunderbird ESR (zh-TW) 153.4.0 | Sep 30, 2026 |
| macOS | |||
| Mozilla Thunderbird | 157.0 | Mozilla Thunderbird 157.0 | Sep 28, 2026 |
| Linux | |||
| MozillaThunderbird · sles 15.7 | 153.4.0-150400.13.6.1 | SUSE-SU-2026:4627-1 | Nov 7, 2026 |
| thunderbird · Debian 12.15 (bookworm) | 1:140.17.0esr-1~deb12u1 | DEBIAN-CVE-2026-103500 | Oct 1, 2026 |
| thunderbird · Debian 13.5 (trixie) | 1:140.17.0esr-1~deb13u1 | DEBIAN-CVE-2026-103500 | Oct 1, 2026 |
| thunderbird · Debian 14 | 1:153.4.0esr-1 | DEBIAN-CVE-2026-103500 | Oct 1, 2026 |
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