CVE-2026-74990
Full vulnerability record from the local CVENow database.
Description
Internally found bugs present in Firefox ESR 115.38, Firefox ESR 140.13, Firefox ESR 153.0 and Firefox 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
Severity
CRITICAL
CVSS score
9.8
(v3.1)
Vulnerability status
Modified
Source identifier
Published
2026-08-18 13:17:40.930000
Last modified
2026-10-28 17:18:42.713000
View original CVE JSON
{
"id": "CVE-2026-74990",
"sourceIdentifier": "[email protected]",
"published": "2026-08-18T13:17:40.930",
"lastModified": "2026-10-28T17:18:42.713",
"vulnStatus": "Modified",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "Internally found bugs present in Firefox ESR 115.38, Firefox ESR 140.13, Firefox ESR 153.0 and Firefox 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1."
}
],
"affected": [
{
"source": "[email protected]",
"affectedData": [
{
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"product": "Firefox",
"versions": [
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"version": "115.39",
"lessThanOrEqual": "115.*",
"versionType": "rpm",
"status": "unaffected"
},
{
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"lessThanOrEqual": "140.*",
"versionType": "rpm",
"status": "unaffected"
},
{
"version": "153.1",
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"versionType": "rpm",
"status": "unaffected"
},
{
"version": "154",
"lessThanOrEqual": "*",
"versionType": "rpm",
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}
]
},
{
"vendor": "Mozilla",
"product": "Thunderbird",
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{
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"lessThanOrEqual": "140.*",
"versionType": "rpm",
"status": "unaffected"
},
{
"version": "153.1",
"lessThanOrEqual": "153.*",
"versionType": "rpm",
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},
{
"version": "154",
"lessThanOrEqual": "*",
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}
]
}
]
}
],
"metrics": {
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"cvssData": {
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"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"baseScore": 9.8,
"baseSeverity": "CRITICAL",
"attackVector": "NETWORK",
"attackComplexity": "LOW",
"privilegesRequired": "NONE",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 3.9,
"impactScore": 5.9
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],
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"id": "CVE-2026-74990",
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{
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{
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"role": "CISA Coordinator",
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}
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}
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"configurations": [
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"source": "[email protected]",
"tags": [
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{
"url": "https://bugzilla.mozilla.org/buglist.cgi?bug_id=2045774%2C2048490%2C2050864%2C2053159%2C2053260%2C2053261%2C2053582%2C2053599%2C2053607%2C2053608%2C2053853%2C2054626%2C2054627%2C2054635%2C2054677%2C2054740%2C2054832%2C2056792%2C2057098%2C2057100%2C2057101%2C2057103%2C2057117%2C2057118%2C2058048%2C2058049%2C2058622%2C2058623%2C2058665%2C2058666%2C2059121%2C2059164%2C2059188",
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"url": "https://www.mozilla.org/security/advisories/mfsa2026-76/",
"source": "[email protected]",
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{
"url": "https://www.mozilla.org/security/advisories/mfsa2026-77/",
"source": "[email protected]",
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}