9.3

CVE-2020-26950: mozilla firefox Use After Free

Modified
AliasesMGASA-2020-0421SUSE-SU-2020:14542-1SUSE-SU-2020:3311-1
Published 09-12-2020Last modified 04-08-2024

Vulnerability summary

CVE-2020-26950 is a high (CVSS 9.3) Use After Free vulnerability in mozilla firefox. EPSS estimates a 42.33% chance of exploitation in the next 30 days, higher than 98.7% of scored vulnerabilities. 3 public exploits are recorded.

Priority
Prioritiseweaponized exploit

Weaponized exploit (Metasploit, 18-11-2020)

Source freshness unavailable

How is this decided?
CVSS score
9.3/10
010
High · v2.0 (NVD)
EPSS score
42.33%
0%100%
High · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits3reference, metasploit

Advisory lineage

Upstream 0 · Downstream 3 · Related 3
OPENSUSE-SU-2024:10600-1OPENSUSE-SU-2024:10601-1OPENSUSE-SU-2024:14572-1

Timeline

  1. 09-12-2020
    PublishedVulnerability first disclosed.
  2. 04-08-2024
    Last modifiedVulnerability information updated.

Description

In certain circumstances, the MCallGetProperty opcode can be emitted with unmet assumptions resulting in an exploitable use-after-free condition. This vulnerability affects Firefox < 82.0.3, Firefox ESR < 78.4.1, and Thunderbird < 78.4.2.

CVSS metrics

6 scores · 5 sources · 3 versions

EPSS trend

Probability

42.33%

Chance of exploitation in the next 30 days

Percentile

99%

Versus all other CVEs

30-day change

No change 0.00 pp

From 42.33% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

3 found
  • referenceUnverified

    Exploit Reference (bugzilla.mozilla.org)

    Maturity: unknown

  • referenceUnverified

    Exploit Reference (packetstormsecurity.com)

    Maturity: unknown

  • MetasploitMetasploitremoteUnverified

    Firefox MCallGetProperty Write Side Effects Use After Free Exploit

    exploit/multi/browser/firefox_jit_use_after_free

    Maturity: poc

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, user interaction (CVSS vector). Other conditions: not stated in public data.

Suse23 products
  • MozillaFirefox&distro=HPE Helion OpenStack 8< 78.4.1-112.32.1
  • MozillaFirefox&distro=SUSE Enterprise Storage 5< 78.4.1-112.32.1
  • MozillaFirefox&distro=SUSE Linux Enterprise Module for Desktop Applications 15 SP1< 78.4.1-3.116.1
  • MozillaFirefox&distro=SUSE Linux Enterprise Module for Desktop Applications 15 SP2< 78.4.1-8.14.1
  • MozillaFirefox&distro=SUSE Linux Enterprise Server 11 SP4-LTSS< 78.4.1-78.102.1
Redhat6 products
  • firefox< 0:78.4.1-1.el7_9 | < 0:78.4.1-1.el8_3 | < 0:78.4.1-1.el6_10 | < 0:78.4.1-1.el8_1 | < 0:78.4.1-1.el8_0 | < 0:78.4.1-1.el8_2
  • firefox-debuginfo< 0:78.4.1-1.el7_9 | < 0:78.4.1-1.el8_3 | < 0:78.4.1-1.el6_10 | < 0:78.4.1-1.el8_1 | < 0:78.4.1-1.el8_0 | < 0:78.4.1-1.el8_2
  • firefox-debugsource< 0:78.4.1-1.el8_3 | < 0:78.4.1-1.el8_1 | < 0:78.4.1-1.el8_0 | < 0:78.4.1-1.el8_2
  • thunderbird< 0:78.4.3-1.el8_3 | < 0:78.4.3-1.el8_2 | < 0:78.4.3-1.el7_9 | < 0:78.4.3-1.el6_10 | < 0:78.4.3-1.el8_1 | < 0:78.4.3-1.el8_0
  • thunderbird-debuginfo< 0:78.4.3-1.el8_3 | < 0:78.4.3-1.el8_2 | < 0:78.4.3-1.el7_9 | < 0:78.4.3-1.el6_10 | < 0:78.4.3-1.el8_1 | < 0:78.4.3-1.el8_0
Alpine5 products
  • firefox< 82.0.3-r0
  • firefox-esr< 78.5.0-r0
  • librewolf< 82.0.3-r0
  • mozjs78< 78.4.1-r0
  • thunderbird< 78.5.1-r0
Ubuntu5 products
  • firefox< 82.0.3+build1-0ubuntu0.16.04.1 | < 82.0.3+build1-0ubuntu0.18.04.1 | < 82.0.3+build1-0ubuntu0.20.04.1
  • mozjs38All versions (No fix recorded)
  • mozjs52All versions (No fix recorded)
  • mozjs68All versions (No fix recorded)
  • thunderbird< 1:78.8.1+build1-0ubuntu0.18.04.1 | < 1:78.7.1+build1-0ubuntu0.20.04.1
Mageia4 products
  • firefox< 78.4.1-1.mga7
  • firefox-l10n< 78.4.1-1.mga7
  • thunderbird< 78.4.2-1.mga7
  • thunderbird-l10n< 78.4.2-1.mga7
Opensuse4 products
  • MozillaFirefox&distro=openSUSE Leap 15.1< 78.4.1-lp151.2.76.1
  • MozillaFirefox&distro=openSUSE Leap 15.2< 78.4.1-lp152.2.27.1
  • MozillaThunderbird&distro=openSUSE Leap 15.1< 78.4.2-lp151.2.56.1
  • MozillaThunderbird&distro=openSUSE Leap 15.2< 78.4.2-lp152.2.16.1
Mozilla3 products
Debian2 products
  • firefox-esr< 78.4.1esr-1~deb10u1 | < 78.4.1esr-1~deb9u1 | < 78.4.1esr-1
  • thunderbird< 1:78.4.2-1~deb10u1 | < 1:78.4.2-1~deb9u1 | < 1:78.4.2-1

8 vendors · 52 products

References

57 links
Show all 57 references