CVE-2018-16840

CRITICAL
9.8
CVSS Score
Published: October 31, 2018 at 06:00 PM UTC
Updated: June 17, 2026 at 01:44 AM UTC
2 products affected across 2 vendorsUbuntu LinuxCurl

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Severity
CRITICAL9.8
Exploit prediction
EPSS 3%
SSVC
No known exploit

Description

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 `Curl_close()` 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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

7.59.0 ≤ v ≤ 7.61.17.59.0 ≤ v < 7.62.0
Affected range stops below 7.62.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (6)

VDB Entryx_refsource_SECTRACKThird Party Advisory
http://www.securitytracker.com/id/1042013
x_refsource_CONFIRMIssue TrackingThird Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16840
x_refsource_MISCPatchVendor Advisory
https://curl.haxx.se/docs/CVE-2018-16840.html
Vendor Advisoryx_refsource_GENTOOThird Party Advisory
https://security.gentoo.org/glsa/201903-03
Vendor Advisoryx_refsource_UBUNTUThird Party Advisory
https://usn.ubuntu.com/3805-1/

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-416

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