CVE-2026-12305
Memory safety bug fixed in Thunderbird 152
02 Description
Memory safety bug fixed in Thunderbird 152
03 Exploitation and scoring
- Exploitation
- Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
- SSVC decision
- ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
- AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
- Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
- EPSS probability
- 0.37% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 31.0% of scored records. A rank, not a probability.
- NVD base score
- 7.5 (CVSS v3.x), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- NVD analysis status
- Modified. NVD last modified this record on 2026-10-26.
- Red Hat severity
- Moderate. Red Hat's rating for its own products, not a CVSS rating.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2026-06-16 11:52Z4 MO AGO
- Last updated
- 2026-10-21 13:50Z8 DAYS AGO
- Reserved
- 2026-06-15
- Assigning CNA
- mozilla
- Record state
- PUBLISHED
- Severity
- High (CVSS 7.5)
- CNA CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weaknesses
- CWE-119Improper Restriction of Operations within the Bounds of a Memory BufferClass
- Data version
- 5.2
- Document digest
- 16675849452588f5208a743d333fb4da490eb9b2c37191641d17f53af1321514
05 Affected products
06 References
- bugzilla.mozilla.orghttps://bugzilla.mozilla.org/show_bug.cgi?id=2037290
- www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2026-57/
- www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2026-58/
- www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2026-60/
- www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2026-61/
07 Fixed in
AlmaLinux 8
- firefox Fixed in 140.12.0-1.el8_10.alma.1
- thunderbird Fixed in 140.12.0-1.el8_10.alma.1
Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
AlmaLinux 9
- firefox Fixed in 140.12.0-1.el9_8.alma.1
- firefox-x11 Fixed in 140.12.0-1.el9_8.alma.1
- thunderbird Fixed in 140.12.0-1.el9_8.alma.1
Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
AlmaLinux 10
- firefox Fixed in 140.12.0-1.el10_2
- thunderbird Fixed in 140.12.0-1.el10_2.alma.1
Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
CloudLinux 8
- firefox Fixed in 140.12.0-1.el8_10.alma.1
- thunderbird Fixed in 140.12.0-1.el8_10.alma.1
Derived from AlmaLinux 8. Partial coverage: only packages taken from AlmaLinux 8 are listed.
Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
CloudLinux 9
- firefox Fixed in 140.12.0-1.el9_8.alma.1
- firefox-x11 Fixed in 140.12.0-1.el9_8.alma.1
- thunderbird Fixed in 140.12.0-1.el9_8.alma.1
Derived from AlmaLinux 9. Partial coverage: only packages taken from AlmaLinux 9 are listed.
Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
CloudLinux 10
- firefox Fixed in 140.12.0-1.el10_2
- thunderbird Fixed in 140.12.0-1.el10_2.alma.1
Derived from AlmaLinux 10. Partial coverage: only packages taken from AlmaLinux 10 are listed.
Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
Debian 12
- firefox-esr Fixed in 140.12.0esr-1~deb12u1
- thunderbird Fixed in 1:140.12.0esr-1~deb12u1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 13
- firefox-esr Fixed in 140.12.0esr-1~deb13u1
- thunderbird Fixed in 1:140.12.0esr-1~deb13u1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 14
- firefox-esr Fixed in 140.12.0esr-1
- thunderbird Fixed in 1:140.12.0esr-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 18.04 LTS
- mozjs38 No fix yet
- mozjs52 No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 20.04 LTS
- mozjs52 No fix yet
- mozjs68 No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 22.04 LTS
- mozjs102 No fix yet
- mozjs78 No fix yet
- mozjs91 No fix yet
- thunderbird No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 24.04 LTS
- mozjs102 No fix yet
- mozjs115 No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.