CVE-2017-7805

CVE-2017-7805 is a high-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-416.

Key facts

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.

Frequently asked questions

What is CVE-2017-7805?
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.
How severe is CVE-2017-7805?
CVE-2017-7805 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2017-7805 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-7805?
CVE-2017-7805 primarily affects Mozilla Firefox. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2017-7805?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2017-7805 published?
CVE-2017-7805 was published on 2018-06-11 and last updated on 2026-06-17.

References

Affected products (6)

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