CVE-2018-16840: Use After Free

Published Oct 31, 2018
·
Updated

A heap use-after-free flaw was found in curl versions from 7.59.0 through 7.61.1 in the code related to closing an easy handle. When closing and cleaning up an 'easy' handle in the Curlclose() function, the library code first frees a struct (without nulling the pointer) and might then subsequently erroneously write to a struct field within that already freed struct.

Affected Software

7 affected componentsFixes available
haxx curl>=7.59.0<=7.61.1
Canonical Ubuntu Linux=14.04
Canonical Ubuntu Linux=16.04
Canonical Ubuntu Linux=18.04
Canonical Ubuntu Linux=18.10
haxx curl>=7.59.0<7.62.0
debian/curl
7.74.0-1.3+deb11u137.74.0-1.3+deb11u167.88.1-10+deb12u147.88.1-10+deb12u58.14.1-2+deb13u28.19.0-38.20.0~rc3-1

Event History

Oct 31, 2018
CVE Published
via MITRE·06:00 PM
Data Sourced
via MITRE·06:00 PM
DescriptionSeverityWeakness
Jan 11, 2024
Data Sourced
via Launchpad·10:54 PM
Description
Feb 20, 2026
Data Sourced
via Ubuntu·05:44 PM
RemedyDescriptionSeverityAffected Software
Apr 24, 2026
Data Sourced
via Debian·09:28 PM
DescriptionAffected Software

Frequently Asked Questions

1

What is the vulnerability ID of this flaw?

The vulnerability ID of this flaw is CVE-2018-16840.

2

What is the severity of CVE-2018-16840?

The severity of CVE-2018-16840 is critical with a severity value of 9.8.

3

Which software versions are affected by CVE-2018-16840?

Curl versions from 7.59.0 through 7.61.1 are affected by CVE-2018-16840.

4

How can I fix CVE-2018-16840?

Upgrade to one of the recommended versions: 7.64.0-4+deb10u2, 7.64.0-4+deb10u7, 7.74.0-1.3+deb11u9, 7.74.0-1.3+deb11u10, 7.88.1-10+deb12u3, 7.88.1-10+deb12u4, or 8.4.0-2.

5

Are there any additional references for CVE-2018-16840?

Yes, you can find additional references for CVE-2018-16840 at the following links: [Reference 1](https://curl.haxx.se/docs/CVE-2018-16840.html), [Reference 2](https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16840), [Reference 3](https://github.com/curl/curl/commit/81d135d67155c5295b1033679c606165d4e28f3f).

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