synced 9 MIN AGO
01 Record

CVE-2020-26959

During browser shutdown, reference decrementing could have occured on a previously freed object, resulting in a use-after-free, memory corruption, and a potentially exploitable crash. This

UnratedPUBLISHEDCNA: mozilla
CNA base scoreUnratedNo CNA CVSS vector

02 Description

During browser shutdown, reference decrementing could have occured on a previously freed object, resulting in a use-after-free, memory corruption, and a potentially exploitable crash. This

03 Exploitation and scoring

Exploitation
Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.
SSVC decision
Not assessed by CISA
EPSS probability
1.29% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 70.1% 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 2026-06-17.
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
2020-12-09 00:22Z5 YR AGO
Last updated
2024-08-04 16:03Z2 YR AGO
Reserved
2020-10-12
Assigning CNA
mozilla
Record state
PUBLISHED
Severity
Not rated by the issuing CNA
CNA CVSS vector
Not published by the issuing CNA
Weaknesses
Data version
5.1
Document digest
b5101a8986d39903cebea3e8cf3adc43eb2f7319835e0ae578467bd22d35ef17

05 Affected products

VendorProductVersionsPlatforms
MozillaFirefox< 83—
MozillaFirefox ESR< 78.5—
MozillaThunderbird< 78.5—

06 References

07 Fixed in

Arch Linux

  • firefox
    Fixed in 83.0-1

Source: Arch Linux Security Tracker, the Arch Linux security team. Reformatted by exploit.cc.

Debian 12

  • firefox-esr
    Fixed in 78.5.0esr-1
  • thunderbird
    Fixed in 1:78.5.0-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 13

  • firefox-esr
    Fixed in 78.5.0esr-1
  • thunderbird
    Fixed in 1:78.5.0-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 14

  • firefox-esr
    Fixed in 78.5.0esr-1
  • thunderbird
    Fixed in 1:78.5.0-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 16.04 LTS

  • firefox
    Fixed in 83.0+build2-0ubuntu0.16.04.3

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 18.04 LTS

  • firefox
    Fixed in 83.0+build2-0ubuntu0.18.04.2
  • mozjs38
    No fix yet
  • mozjs52
    No fix yet
  • thunderbird
    Fixed in 1:78.8.1+build1-0ubuntu0.18.04.1

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 20.04 LTS

  • firefox
    Fixed in 83.0+build2-0ubuntu0.20.04.1
  • mozjs52
    No fix yet
  • mozjs68
    No fix yet
  • thunderbird
    Fixed in 1:78.7.1+build1-0ubuntu0.20.04.1

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.