Critical 9.8Published Jul 21, 2026

CVE-2026-16360Memory safety bugs fixed in Thunderbird ESR 140.13 and Thunderbird 153

Updated under an hour ago (Oct 26, 2026, 1:23 PM ET)

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It affects Mozilla Firefox and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

Memory safety bugs present in Thunderbird ESR 140.12 and Thunderbird 152. 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 153, Firefox ESR 115.38, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.

CVSS: 9.8 CRITICAL (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-119
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: mozilla
NVD analysis: Modified
Record last updated: Oct 21, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Mozilla Firefox mozilla:firefox (from the name)	115.38 builds before 115.* not affected; 140.13 builds before 140.* not affected; from 153 not affected	CNA record
Mozilla Thunderbird mozilla:thunderbird (from the name)	140.13 builds before 140.* not affected; from 153 not affected	CNA record
mozilla firefox mozilla:firefox	before 115.38.0; before 153.0.0; from 128.1.0 before 140.13.0	NVD
mozilla thunderbird mozilla:thunderbird	before 140.13.0; from 141.0 before 153.0	NVD

References

References

https://bugzilla.mozilla.org/buglist.cgi?bug_id=2022635%2C2028004%2C2035756%2C2045184%2C2045185%2C2045198%2C2045392%2C2045395%2C2045396%2C2045397%2C2045405%2C2045414%2C2045415%2C2045451%2C2045454%2C2045508%2C2045510%2C2045513%2C2045515%2C2045518%2C2045604%2C2045607%2C2045612%2C2045617%2C2045619%2C2045624%2C2045625%2C2045729%2C2045737%2C2045741%2C2045742%2C2045763%2C2045767%2C2045770%2C2045772%2C2045773%2C2045783%2C2045833%2C2045848%2C2045865%2C2045875%2C2045957%2C2047723%2C2047729%2C2048795%2C2048799%2C2048801%2C2049392%2C2049397%2C2049398%2C2049399%2C2049404%2C2049405%2C2049407%2C2049812%2C2050657%2C2050668%2C2050990%2C2053166%2C2053273%2C2053576%2C2053583%2C2053587	broken-link
https://bugzilla.mozilla.org/buglist.cgi?bug_id=2043739%2C2045281%2C2045614%2C2045744%2C2045775%2C2047719%2C2049805%2C2051666	permissions-required
https://www.mozilla.org/security/advisories/mfsa2026-68/	vendor-advisory
https://www.mozilla.org/security/advisories/mfsa2026-69/	vendor-advisory
https://www.mozilla.org/security/advisories/mfsa2026-70/	vendor-advisory
https://www.mozilla.org/security/advisories/mfsa2026-71/	vendor-advisory
https://www.mozilla.org/security/advisories/mfsa2026-72/	vendor-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.