Inside the JavaScript parser, a cast of an integer to a narrower type can result in data read from outside the buffer being parsed.

Published 8 y ago 2018-06-11 · modified 4 mo ago 2026-06-17 · JSON

CVSS

8.2

v3.0 · NVD

CISA KEV

not known exploited

EPSS

1.6%

percentile 75%

Public exploits

none known

Inside the JavaScript parser, a cast of an integer to a narrower type can result in data read from outside the buffer being parsed. This usually results in a non-exploitable crash, but can leak a limited amount of information from memory if it matches JavaScript identifier syntax. This vulnerability affects Firefox < 56.

Exploit prediction (EPSS)

1.56% probability of exploitation in the next 30 days, higher than 75% of all scored CVEs.

CVSS scores

Assigned by	Version	Score	Vector
NVD	3.0	8.2	`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H`
NVD	2.0	6.4	`AV:N/AC:L/Au:N/C:P/I:N/A:P`

Affected products

Mozilla Firefox

Classification

Weakness

CWE-125 Out-of-bounds Read
CWE-704 Incorrect Type Conversion or Cast

References

bugzilla.mozilla.org /show_bug.cgi?id=1383951 · x_refsource_CONFIRM, x_transferred
securitytracker.com /id/1039465 · vdb-entry, x_refsource_SECTRACK, x_transferred
mozilla.org /security/advisories/mfsa2017-21/ · x_refsource_CONFIRM, x_transferred
securityfocus.com /bid/101057 · vdb-entry, x_refsource_BID, x_transferred

Sources

CVE List: CVE-2017-7813
NVD: CVE-2017-7813

vulnwire keeps one entry per vulnerability: the CVE id wins, then GHSA; records that alias each other are merged. Machine-readable: JSON.