Out-of-bounds Write Affecting curl package, versions <8.4.0-r0


0.0
critical
0
10

Snyk CVSS

    Attack Complexity Low
    Confidentiality High
    Integrity High
    Availability High

    Threat Intelligence

    EPSS 0.32% (71st percentile)
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NVD
9.8 critical
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SUSE
8.1 high
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Red Hat
8.1 high

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  • Snyk ID SNYK-ALPINE318-CURL-5958913
  • published 11 Oct 2023
  • disclosed 18 Oct 2023

How to fix?

Upgrade Alpine:3.18 curl to version 8.4.0-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream curl package and not the curl package as distributed by Alpine. See How to fix? for Alpine:3.18 relevant fixed versions and status.

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.