CVE-2026-8973

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.
• AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
• Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.36% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 30.3% of scored records. A rank, not a probability.

NVD base score

8.8 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

NVD analysis status

Modified. NVD last modified this record on 2026-10-21.

Red Hat severity

Important. 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.

Published

2026-05-19 12:30Z5 MO AGO

Last updated

2026-10-21 13:50Z7 DAYS AGO

Reserved

2026-05-19

Assigning CNA

mozilla

Record state

PUBLISHED

Severity

High (CVSS 8.8)

CNA CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Weaknesses

• CWE-119Improper Restriction of Operations within the Bounds of a Memory BufferClass
• CWE-787Out-of-bounds WriteBase

Data version

5.2

Document digest

559f00fc31ab58d205879943680e9a4a5c785ab52d6d63a4cb4d1683acd0c11f

• bugzilla.mozilla.orgMemory safety bugs fixed in Thunderbird 151https://bugzilla.mozilla.org/buglist.cgi?bug_id=1362365%2C1860538%2C1929005%2C1983353%2C1998526%2C2023271%2C2023943%2C2024244%2C2024260%2C2024443%2C2024665%2C2024774%2C2024916%2C2025346%2C2025357%2C2025406%2C2025434%2C2025488%2C2025496%2C2025942%2C2025947%2C2025968%2C2026279%2C2027159%2C2027239%2C2027276%2C2027308%2C2027310%2C2027324%2C2027329%2C2027363%2C2027381%2C2027382%2C2027383%2C2028274%2C2028884%2C2029060%2C2029065%2C2029068%2C2029281%2C2029293%2C2029297%2C2029303%2C2029439%2C2029448%2C2029703%2C2029720%2C2029721%2C2029723%2C2029770%2C2029771%2C2029782%2C2029818%2C2029885%2C2030100%2C2030379%2C2030385%2C2030979%2C2031119%2C2031122%2C2034119%2C2034791%2C2035209%2C2036666%2C2037986
• www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2026-46/
• www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2026-50/
• access.redhat.comhttps://access.redhat.com/security/cve/CVE-2026-8973vdb-entryx_refsource_REDHAT
• bugzilla.redhat.comRHBZ#2479864https://bugzilla.redhat.com/show_bug.cgi?id=2479864issue-trackingx_refsource_REDHAT
• security.access.redhat.comhttps://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-8973.jsonx_sadp-csaf-vex