CVE-2026-74990

Internally found bugs present in Thunderbird ESR 140.13, Thunderbird ESR 153.0 and Thunderbird 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.

CVSS v3 9.8 CRITICAL

9.8^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://bugzilla.mozilla.org/buglist.cgi?bug_id=2045762%2C2052401%2C2058208	Broken Link
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	Broken Link
https://www.mozilla.org/security/advisories/mfsa2026-74/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-75/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-76/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-77/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-78/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-79/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-80/	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:mozilla:firefox::::::::
	cpe:2.3:a:mozilla:firefox::::::::
	cpe:2.3:a:mozilla:firefox::::::::
	cpe:2.3:a:mozilla:thunderbird::::::::
	cpe:2.3:a:mozilla:thunderbird::::::::

History

No history.

Information

Published : 2026-08-18 13:17

Updated : 2026-09-01 22:17

NVD link : CVE-2026-74990

Mitre link : CVE-2026-74990

CVE.ORG link : CVE-2026-74990

JSON object : View

Products Affected

mozilla

thunderbird
firefox

CWE

CWE-119

Improper Restriction of Operations within the Bounds of a Memory Buffer

{"id": "CVE-2026-74990", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-74990", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "total"}], "version": "2.0.3", "timestamp": "2026-08-18T19:27:52.706061Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 9.8, "attackVector": "NETWORK", "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 3.9}]}, "affected": [{"source": "security@mozilla.org", "affectedData": [{"vendor": "Mozilla", "product": "Firefox", "versions": [{"status": "unaffected", "version": "115.39", "versionType": "rpm", "lessThanOrEqual": "115.*"}, {"status": "unaffected", "version": "140.14", "versionType": "rpm", "lessThanOrEqual": "140.*"}, {"status": "unaffected", "version": "153.1", "versionType": "rpm", "lessThanOrEqual": "153.*"}, {"status": "unaffected", "version": "154", "versionType": "rpm", "lessThanOrEqual": "*"}]}, {"vendor": "Mozilla", "product": "Thunderbird", "versions": [{"status": "unaffected", "version": "140.14", "versionType": "rpm", "lessThanOrEqual": "140.*"}, {"status": "unaffected", "version": "153.1", "versionType": "rpm", "lessThanOrEqual": "153.*"}, {"status": "unaffected", "version": "154", "versionType": "rpm", "lessThanOrEqual": "*"}]}]}], "published": "2026-08-18T13:17:40.930", "references": [{"url": "https://bugzilla.mozilla.org/buglist.cgi?bug_id=2045762%2C2052401%2C2058208", "tags": ["Broken Link"], "source": "security@mozilla.org"}, {"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", "tags": ["Broken Link"], "source": "security@mozilla.org"}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-74/", "tags": ["Vendor Advisory"], "source": "security@mozilla.org"}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-75/", "tags": ["Vendor Advisory"], "source": "security@mozilla.org"}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-76/", "tags": ["Vendor Advisory"], "source": "security@mozilla.org"}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-77/", "tags": ["Vendor Advisory"], "source": "security@mozilla.org"}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-78/", "tags": ["Vendor Advisory"], "source": "security@mozilla.org"}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-79/", "tags": ["Vendor Advisory"], "source": "security@mozilla.org"}, {"url": "https://www.mozilla.org/security/advisories/mfsa2026-80/", "tags": ["Vendor Advisory"], "source": "security@mozilla.org"}], "vulnStatus": "Modified", "weaknesses": [{"type": "Secondary", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "description": [{"lang": "en", "value": "CWE-119"}]}], "descriptions": [{"lang": "en", "value": "Internally found bugs present in Thunderbird ESR 140.13, Thunderbird ESR 153.0 and Thunderbird 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."}], "lastModified": "2026-09-01T22:17:12.520", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "FD8DBFC4-10A7-41E2-B754-71CC6FEEBB5C", "versionEndExcluding": "115.39.0"}, {"criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "502016C0-F897-4F18-BFC7-301B71D93E4D", "versionEndExcluding": "140.14.0", "versionStartIncluding": "116.0"}, {"criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "5D58C9D3-E300-408A-ABF2-6E2BB49AB921", "versionEndExcluding": "153.1.0", "versionStartIncluding": "141.0"}, {"criteria": "cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "4E2EC2AA-23B2-45C9-8594-DF80A0D800A7", "versionEndExcluding": "140.14.0"}, {"criteria": "cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "47206424-A249-46CE-9776-F45A49344204", "versionEndExcluding": "153.1.0", "versionStartIncluding": "141.0"}], "operator": "OR"}]}], "sourceIdentifier": "security@mozilla.org"}