CVE-2023-38545

Publication date 11 October 2023

Last updated 24 July 2024

Ubuntu priority

Cvss 3 Severity Score

This flaw makes curl overflow a heap based buffer in the SOCKS5 proxy handshake. When curl is asked to pass along the host name to the SOCKS5 proxy to allow that to resolve the address instead of it getting done by curl itself, the maximum length that host name can be is 255 bytes. If the host name is detected to be longer, curl switches to local name resolving and instead passes on the resolved address only. Due to this bug, the local variable that means "let the host resolve the name" could get the wrong value during a slow SOCKS5 handshake, and contrary to the intention, copy the too long host name to the target buffer instead of copying just the resolved address there. The target buffer being a heap based buffer, and the host name coming from the URL that curl has been told to operate with.

Read the notes from the security team

Why is this CVE high priority?

Upstream curl developer has rated this issue as high

Learn more about Ubuntu priority

Status

Show unmaintained releases

Package	Ubuntu Release	Status
curl	24.04 LTS noble	Fixed 8.2.1-1ubuntu3.1
	23.10 mantic	Fixed 8.2.1-1ubuntu3.1
	23.04 lunar	Fixed 7.88.1-8ubuntu2.3
	22.04 LTS jammy	Fixed 7.81.0-1ubuntu1.14
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not affected
	14.04 LTS trusty	Not affected

Notes

mdeslaur

affects 7.69 and higher introduced in https://github.com/curl/curl/commit/4a4b63daaa

Severity score breakdown

Parameter	Value
Base score	9.8 · Critical
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	High
Integrity impact	High
Availability impact	High
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H