SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2021-43539

This could have led to a use-after-free causing a potentially exploitable crash.

HIGH 8.8EPSS 1.62%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (1.62%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

Failure to correctly record the location of live pointers across wasm instance calls resulted in a GC occurring within the call not tracing those live pointers. This could have led to a use-after-free causing a potentially exploitable crash. This vulnerability affects Thunderbird < 91.4.0, Firefox ESR < 91.4.0, and Firefox < 95.

CVSS 3.1
8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS
1.62% probability · 75th percentile
CISA KEV
Not listed
Weakness
CWE-416
Affected
mozilla/firefox · mozilla/firefox esr · mozilla/thunderbird · debian/debian linux
Source
security@mozilla.org

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.