SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2017-7805

This leaves a pointer pointing to the old, freed buffer, resulting in a use-after-free when handshake hashes are then calculated afterwards.

HIGH 7.5EPSS 3.11%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (3.11%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

During TLS 1.2 exchanges, handshake hashes are generated which point to a message buffer. This saved data is used for later messages but in some cases, the handshake transcript can exceed the space available in the current buffer, causing the allocation of a new buffer. This leaves a pointer pointing to the old, freed buffer, resulting in a use-after-free when handshake hashes are then calculated afterwards. This can result in a potentially exploitable crash. This vulnerability affects Firefox < 56, Firefox ESR < 52.4, and Thunderbird < 52.4.

CVSS 3.0
7.5 HIGHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
3.11% probability · 87th percentile
CISA KEV
Not listed
Weakness
CWE-416
Affected
mozilla/firefox · mozilla/thunderbird · debian/debian linux
Source
security@mozilla.org

References

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