The URL percent-encoding decode function in libcurl before 7.51.0 is called `curl_easy_unescape`. Internally, even if this function would be made to allocate a unscape destination buffer larger than 2GB, it would return that new length in a signed 32 bit integer variable, thus the length would get either just truncated or both truncated and turned negative. That could then lead to libcurl writing outside of its heap based buffer.



Source: MITRE

Published: 2018-07-31

Updated: 2018-11-13

Type: CWE-787

Risk Information

CVSS v2.0

Base Score: 7.5

Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P

Impact Score: 6.4

Exploitability Score: 10

Severity: HIGH

CVSS v3.0

Base Score: 9.8

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Impact Score: 5.9

Exploitability Score: 3.9

Severity: CRITICAL