CVE-2026-6785
published 2026-04-26CVE-2026-6785: Memory safety bugs present in Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149 and Thunderbird 149. Some of these bugs showed evidence…
PriorityP344high7.5CVSS 3.1
AVNACHPRNUIRSUCHIHAH
EPSS
0.51%
40.3th percentile
Memory safety bugs present in Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149 and Thunderbird 149. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 150, Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
Affected
9 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 150 | Firefox 150 |
| mozilla | firefox | < 115.35.0 | 115.35.0 |
| mozilla | firefox | < 150.0 | 150.0 |
| mozilla | firefox | >= 140.0 < 140.10.0 | 140.10.0 |
| mozilla | firefox_esr | < Firefox ESR 140.10 | Firefox ESR 140.10 |
| mozilla | firefox_esr | < Firefox ESR 115.35 | Firefox ESR 115.35 |
| mozilla | thunderbird | < Thunderbird 140.10 | Thunderbird 140.10 |
| mozilla | thunderbird | < Thunderbird 150 | Thunderbird 150 |
| mozilla | thunderbird | >= 140.0 < 140.10.0 | 140.10.0 |
CVSS provenance
nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
vendor_redhat8.1HIGH
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Red Hat
firefox: thunderbird: Memory safety bugs fixed in Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird ESR 140.10, Firefox 150 and Thunderbird 150
vendor_redhat·2026-04-21·CVSS 8.1
CVE-2026-6785 [HIGH] CWE-787 firefox: thunderbird: Memory safety bugs fixed in Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird ESR 140.10, Firefox 150 and Thunderbird 150
firefox: thunderbird: Memory safety bugs fixed in Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird ESR 140.10, Firefox 150 and Thunderbird 150
A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue:
Memory safety bugs present in Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149 and Thunderbird 149. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.
Statement: Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.
Mozilla
Mozilla Foundation Security Advisory 2026-32: CVE-2026-6785
vendor_mozilla·CVSS 8.1
CVE-2026-6785 [HIGH] Mozilla Foundation Security Advisory 2026-32: CVE-2026-6785
Mozilla Foundation Security Advisory 2026-32
CVE: CVE-2026-6785
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 140.10
Mozilla
Mozilla Foundation Security Advisory 2026-31: CVE-2026-6785
vendor_mozilla·CVSS 8.1
CVE-2026-6785 [HIGH] Mozilla Foundation Security Advisory 2026-31: CVE-2026-6785
Mozilla Foundation Security Advisory 2026-31
CVE: CVE-2026-6785
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 115.35
Mozilla
Mozilla Foundation Security Advisory 2026-34: CVE-2026-6785
vendor_mozilla·CVSS 8.1
CVE-2026-6785 [HIGH] Mozilla Foundation Security Advisory 2026-34: CVE-2026-6785
Mozilla Foundation Security Advisory 2026-34
CVE: CVE-2026-6785
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140.10
Mozilla
Mozilla Foundation Security Advisory 2026-33: CVE-2026-6785
vendor_mozilla·CVSS 8.1
CVE-2026-6785 [HIGH] Mozilla Foundation Security Advisory 2026-33: CVE-2026-6785
Mozilla Foundation Security Advisory 2026-33
CVE: CVE-2026-6785
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 150
Mozilla
Mozilla Foundation Security Advisory 2026-30: CVE-2026-6785
vendor_mozilla·CVSS 8.1
CVE-2026-6785 [HIGH] Mozilla Foundation Security Advisory 2026-30: CVE-2026-6785
Mozilla Foundation Security Advisory 2026-30
CVE: CVE-2026-6785
Product: Firefox
Impact: high
Fixed in: Firefox 150
VulDB
Mozilla Firefox up to 149 memory corruption (Nessus ID 307899 / WID-SEC-2026-1228)
vuldb·2026-05-21·CVSS 8.1
CVE-2026-6785 [HIGH] Mozilla Firefox up to 149 memory corruption (Nessus ID 307899 / WID-SEC-2026-1228)
A vulnerability, which was classified as critical, was found in Mozilla Firefox up to 149. Affected by this issue is some unknown functionality. The manipulation results in memory corruption.
This vulnerability was named CVE-2026-6785. The attack may be performed from remote. There is no available exploit.
You should upgrade the affected component.
GHSA
GHSA-xq45-h54c-3xfp: Memory safety bugs present in Firefox ESR 115
ghsa_unreviewed·2026-04-26
CVE-2026-6785 [HIGH] CWE-125 GHSA-xq45-h54c-3xfp: Memory safety bugs present in Firefox ESR 115
Memory safety bugs present in Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149 and Thunderbird 149. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 150, Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
No detection rules found.
No public exploits indexed.
https://bugzilla.mozilla.org/buglist.cgi?bug_id=1935995%2C1999158%2C2015952%2C2021909%2C2022026%2C2022041%2C2022088%2C2022276%2C2022335%2C2022338%2C2022373%2C2022597%2C2022874%2C2023276%2C2023544%2C2023551%2C2023599%2C2023608%2C2023814%2C2024233%2C2024239%2C2024241%2C2024242%2C2024250%2C2024251%2C2024343%2C2024422%2C2024425%2C2024440%2C2024442%2C2024446%2C2024458%2C2024463%2C2024478%2C2024650%2C2024653%2C2024654%2C2024655%2C2024656%2C2024661%2C2024662%2C2024668%2C2024919%2C2025278%2C2025349%2C2025350%2C2025354%2C2025360%2C2025363%2C2025370%2C2025379%2C2025381%2C2025399%2C2025400%2C2025403%2C2025407%2C2025415%2C2025420%2C2025427%2C2025429%2C2025430%2C2025479%2C2025489%2C2025493%2C2025497%2C2025502%2C2025515%2C2025517%2C2025526%2C2025609%2C2025948%2C2025949%2C2025951%2C2025953%2C2025955%2C2025962%2C2025969%2C2025970%2C2025971%2C2025973%2C2025976%2C2025977%2C2026280%2C2026285%2C2026293%2C2026296%2C2026310%2C2027237%2C2027260%2C2027268%2C2027277%2C2027284%2C2027291%2C2027293%2C2027298%2C2027330%2C2027342%2C2027345%2C2027359%2C2027365%2C2027378%2C2027754%2C2027959%2C2027962%2C2027964%2C2027971%2C2027974%2C2027979%2C2027982%2C2027995%2C2028001%2C2028267%2C2028268%2C2028275%2C2028288%2C2028290%2C2028291%2C2028528%2C2028551%2C2028627%2C2028879%2C2028889%2C2029061%2C2029071%2C2029283%2C2029296%2C2029314%2C2029323%2C2029411%2C2029423%2C2029424%2C2029425%2C2029427%2C2029436%2C2029440%2C2029449%2C2029450%2C2029458%2C2029462%2C2029468%2C2029472%2C2029690%2C2029707%2C2029708%2C2029728%2C2029802%2C2029896%2C2029906%2C2030106%2C2030118%2C2030123%2C2030135%2C2030230%2C2030320https://www.mozilla.org/security/advisories/mfsa2026-30/https://www.mozilla.org/security/advisories/mfsa2026-31/https://www.mozilla.org/security/advisories/mfsa2026-32/https://www.mozilla.org/security/advisories/mfsa2026-33/https://www.mozilla.org/security/advisories/mfsa2026-34/https://access.redhat.com/errata/RHSA-2026:10757https://access.redhat.com/errata/RHSA-2026:10766https://access.redhat.com/errata/RHSA-2026:10767https://access.redhat.com/errata/RHSA-2026:12285https://access.redhat.com/errata/RHSA-2026:13537https://access.redhat.com/errata/RHSA-2026:15892https://access.redhat.com/errata/RHSA-2026:17477https://access.redhat.com/errata/RHSA-2026:17687https://access.redhat.com/errata/RHSA-2026:17688https://access.redhat.com/errata/RHSA-2026:17689https://access.redhat.com/errata/RHSA-2026:17690https://access.redhat.com/errata/RHSA-2026:19041https://access.redhat.com/errata/RHSA-2026:19131https://access.redhat.com/errata/RHSA-2026:19201https://access.redhat.com/errata/RHSA-2026:19348https://access.redhat.com/errata/RHSA-2026:19461https://access.redhat.com/errata/RHSA-2026:19462https://access.redhat.com/errata/RHSA-2026:19463https://access.redhat.com/errata/RHSA-2026:19464https://access.redhat.com/errata/RHSA-2026:19465https://access.redhat.com/errata/RHSA-2026:19466https://access.redhat.com/errata/RHSA-2026:19467https://access.redhat.com/errata/RHSA-2026:19468https://access.redhat.com/errata/RHSA-2026:19469https://access.redhat.com/errata/RHSA-2026:19542https://access.redhat.com/errata/RHSA-2026:19655https://access.redhat.com/errata/RHSA-2026:19704https://access.redhat.com/security/cve/CVE-2026-6785https://bugzilla.redhat.com/show_bug.cgi?id=2460104https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-6785.json
2026-04-26
Published