CVE-2026-100771
published 2026-09-29CVE-2026-100771: Undefined behavior in the DOM: Streams component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4…
PriorityP341high8.1CVSS 3.1
AVNACLPRNUIRSUCHIHAN
EPSS
0.31%
22.1th percentile
Undefined behavior in the DOM: Streams component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.
Affected
18 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 157 | Firefox 157 |
| mozilla | firefox | — | — |
| mozilla | firefox | >= 115.0 < 115.42.0 | 115.42.0 |
| mozilla | firefox | >= 140.0.0 < 140.17.0 | 140.17.0 |
| mozilla | firefox | >= 153.0 < 153.4.0 | 153.4.0 |
| mozilla | firefox | >= 154.0.0 < 157.0.0 | 157.0.0 |
| mozilla | firefox_esr | < Firefox ESR 153.4 | Firefox ESR 153.4 |
| mozilla | firefox_esr | < Firefox ESR 115.42 | Firefox ESR 115.42 |
| mozilla | firefox_esr | < Firefox ESR 140.17 | Firefox ESR 140.17 |
| mozilla | thunderbird | < Thunderbird 140.17 | Thunderbird 140.17 |
| mozilla | thunderbird | < Thunderbird 157 | Thunderbird 157 |
| mozilla | thunderbird | < Thunderbird 153.4 | Thunderbird 153.4 |
| mozilla | thunderbird | — | — |
| mozilla | thunderbird | >= 140.0 < 140.17.0 | 140.17.0 |
| mozilla | thunderbird | >= 153.0 < 153.4.0 | 153.4.0 |
| mozilla | thunderbird | >= 154.0 < 157.0 | 157.0 |
| rhel10 | firefox-flatpak | — | — |
| rhel10 | thunderbird-flatpak | — | — |
CVSS provenance
nvdv3.18.1HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
vendor_redhat8.1HIGH
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Red Hat
firefox: thunderbird: Undefined behavior in the DOM: Streams component
vendor_redhat·2026-09-29·CVSS 8.1
CVE-2026-100771 [HIGH] CWE-758 firefox: thunderbird: Undefined behavior in the DOM: Streams component
firefox: thunderbird: Undefined behavior in the DOM: Streams component
Undefined behavior in the DOM: Streams component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.
A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue:
Undefined behavior in the DOM: Streams component
Statement: Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.
Mitigation: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread in
Mozilla
Mozilla Foundation Security Advisory 2026-102: CVE-2026-100771
vendor_mozilla
CVE-2026-100771 Mozilla Foundation Security Advisory 2026-102: CVE-2026-100771
Mozilla Foundation Security Advisory 2026-102
CVE: CVE-2026-100771
Product: Thunderbird
Impact: moderate
Fixed in: Thunderbird 140.17
Mozilla
Mozilla Foundation Security Advisory 2026-101: CVE-2026-100771
vendor_mozilla
CVE-2026-100771 Mozilla Foundation Security Advisory 2026-101: CVE-2026-100771
Mozilla Foundation Security Advisory 2026-101
CVE: CVE-2026-100771
Product: Thunderbird
Impact: low
Fixed in: Thunderbird 157
Mozilla
Mozilla Foundation Security Advisory 2026-100: CVE-2026-100771
vendor_mozilla
CVE-2026-100771 Mozilla Foundation Security Advisory 2026-100: CVE-2026-100771
Mozilla Foundation Security Advisory 2026-100
CVE: CVE-2026-100771
Product: Firefox ESR
Impact: low
Fixed in: Firefox ESR 153.4
Mozilla
Mozilla Foundation Security Advisory 2026-97: CVE-2026-100771
vendor_mozilla
CVE-2026-100771 Mozilla Foundation Security Advisory 2026-97: CVE-2026-100771
Mozilla Foundation Security Advisory 2026-97
CVE: CVE-2026-100771
Product: Firefox
Impact: low
Fixed in: Firefox 157
Mozilla
Mozilla Foundation Security Advisory 2026-98: CVE-2026-100771
vendor_mozilla
CVE-2026-100771 Mozilla Foundation Security Advisory 2026-98: CVE-2026-100771
Mozilla Foundation Security Advisory 2026-98
CVE: CVE-2026-100771
Product: Firefox ESR
Impact: moderate
Fixed in: Firefox ESR 115.42
Mozilla
Mozilla Foundation Security Advisory 2026-99: CVE-2026-100771
vendor_mozilla
CVE-2026-100771 Mozilla Foundation Security Advisory 2026-99: CVE-2026-100771
Mozilla Foundation Security Advisory 2026-99
CVE: CVE-2026-100771
Product: Firefox ESR
Impact: moderate
Fixed in: Firefox ESR 140.17
Mozilla
Mozilla Foundation Security Advisory 2026-103: CVE-2026-100771
vendor_mozilla
CVE-2026-100771 Mozilla Foundation Security Advisory 2026-103: CVE-2026-100771
Mozilla Foundation Security Advisory 2026-103
CVE: CVE-2026-100771
Product: Thunderbird
Impact: low
Fixed in: Thunderbird 153.4
VulDB
Mozilla Firefox up to 115.41/140.16/153.3/156 Streams reliance on undefined, unspecified, or implementation-defined behavior (WID-SEC-2026-3654)
vuldb·2026-10-03·CVSS 8.1
CVE-2026-100771 [HIGH] Mozilla Firefox up to 115.41/140.16/153.3/156 Streams reliance on undefined, unspecified, or implementation-defined behavior (WID-SEC-2026-3654)
A vulnerability has been found in Mozilla Firefox up to 115.41/140.16/153.3/156 and classified as critical. This vulnerability affects unknown code of the component Streams. This manipulation causes reliance on undefined, unspecified, or implementation-defined behavior.
This vulnerability is tracked as CVE-2026-100771. The attack is possible to be carried out remotely. No exploit exists.
The affected component should be upgraded.
GHSA
Undefined behavior in the DOM: Streams component.
ghsa_unreviewed·2026-09-29
CVE-2026-100771 Undefined behavior in the DOM: Streams component.
Undefined behavior in the DOM: Streams component. This vulnerability was fixed in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.
No detection rules found.
No public exploits indexed.
https://bugzilla.mozilla.org/show_bug.cgi?id=2068336https://www.mozilla.org/security/advisories/mfsa2026-100/https://www.mozilla.org/security/advisories/mfsa2026-101/https://www.mozilla.org/security/advisories/mfsa2026-102/https://www.mozilla.org/security/advisories/mfsa2026-103/https://www.mozilla.org/security/advisories/mfsa2026-97/https://www.mozilla.org/security/advisories/mfsa2026-98/https://www.mozilla.org/security/advisories/mfsa2026-99/
2026-09-29
Published