CVE-2026-110247
published 2026-10-13CVE-2026-110247: Several buffer-growth sites in libmime performed size arithmetic in 32-bit types without overflow checks. On a sufficiently large message the growth guard…
PriorityP344high8.4CVSS 3.1
AVLACLPRNUINSUCHIHAH
EPSS
0.17%
6.7th percentile
Several buffer-growth sites in libmime performed size arithmetic in 32-bit types without overflow checks. On a sufficiently large message the growth guard could fail open, or the buffer could be reallocated smaller than required, and a subsequent memcpy would then write attacker-controlled data across adjacent heap allocations. This vulnerability was fixed in Thunderbird 158 and Thunderbird 153.6.
Affected
3 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | thunderbird | < Thunderbird 158 | Thunderbird 158 |
| mozilla | thunderbird | < Thunderbird 153.6 | Thunderbird 153.6 |
| mozilla | thunderbird | — | — |
CVSS provenance
nvdv3.18.4HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
vendor_redhat8.8HIGH
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Red Hat
thunderbird: thunderbird: Arbitrary code execution via integer overflow in libmime
vendor_redhat·2026-10-13·CVSS 8.8
CVE-2026-110247 [HIGH] CWE-787 thunderbird: thunderbird: Arbitrary code execution via integer overflow in libmime
thunderbird: thunderbird: Arbitrary code execution via integer overflow in libmime
A flaw was found in Thunderbird. A remote attacker could exploit an integer overflow in the libmime library to achieve arbitrary code execution or cause a Denial of Service (DoS). By sending a sufficiently large email message, an attacker causes buffer size arithmetic to overflow without proper checks. This leads to heap memory corruption as subsequent memory copy operations overwrite adjacent heap allocations with attacker-controlled data.
Package: thunderbird (Red Hat Enterprise Linux 10) - Affected
Package: thunderbird (Red Hat Enterprise Linux 8) - Affected
Package: thunderbird (Red Hat Enterprise Linux 9) - Affected
Mozilla
Mozilla Foundation Security Advisory 2026-109: CVE-2026-110247
vendor_mozilla
CVE-2026-110247 Mozilla Foundation Security Advisory 2026-109: CVE-2026-110247
Mozilla Foundation Security Advisory 2026-109
CVE: CVE-2026-110247
Product: Thunderbird
Impact: low
Fixed in: Thunderbird 158
Mozilla
Mozilla Foundation Security Advisory 2026-122: CVE-2026-110247
vendor_mozilla·CVSS 8.4
CVE-2026-110247 [HIGH] Mozilla Foundation Security Advisory 2026-122: CVE-2026-110247
Mozilla Foundation Security Advisory 2026-122
CVE: CVE-2026-110247
Product: Thunderbird
Impact: low
Fixed in: Thunderbird 153.6
GHSA
Several buffer-growth sites in libmime performed size arithmetic in 32-bit types without overflow checks.
ghsa_unreviewed·2026-10-13
CVE-2026-110247 Several buffer-growth sites in libmime performed size arithmetic in 32-bit types without overflow checks.
Several buffer-growth sites in libmime performed size arithmetic in 32-bit types without overflow checks. On a sufficiently large message the growth guard could fail open, or the buffer could be reallocated smaller than required, and a subsequent memcpy would then write attacker-controlled data across adjacent heap allocations. This vulnerability was fixed in Thunderbird 158.
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
2026-10-13
Published