CVE-2018-16840

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-13. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 3.4%CVSS: 9.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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.

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
45
EG Risk 45/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation3% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
3.4%
EPSS %ILE
88th
KEV
Not listed

CISA SSVCTrack at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

October 31, 2018

Last Modified

April 17, 2025

Advisory Details (5)

Auto-updated Oct 2, 2026
Patch available. Sources: redhat, github_commit.
github_commit

commit 81d135d67155 (curl/curl)

Fix landed in curl/curl commit 81d135d67155 — awaiting tagged release

https://github.com/curl/curl/commit/81d135d67155c5295b1033679c606165d4e28f3f
generic

curl - use after free in handle close - CVE-2018-16840

https://curl.haxx.se/docs/CVE-2018-16840.html
redhat Patch Available

1642203 – (CVE-2018-16840) CVE-2018-16840 curl: Use-after-free when closing "easy" handle in Curl_close()

https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16840
generic

cURL: Multiple vulnerabilities (GLSA 201903-03) — Gentoo security

https://security.gentoo.org/glsa/201903-03
generic
http://www.securitytracker.com/id/1042013

Patch Availability(2)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulibcurl4-openssl-dev (7.35.0-1ubuntu2.19) @ trusty2026-05-28ubuntu
redhatpatch2019-06-18redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(24 across 24 ecosystems)
Alpine:v3.10(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.59.0 up to 7.62.0-r0: fixed in 7.62.0-r0
—
Alpine:v3.11(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.59.0 up to 7.62.0-r0: fixed in 7.62.0-r0
—
Alpine:v3.12(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.59.0 up to 7.62.0-r0: fixed in 7.62.0-r0
—
Alpine:v3.13(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.59.0 up to 7.62.0-r0: fixed in 7.62.0-r0
—
Alpine:v3.14(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.59.0 up to 7.62.0-r0: fixed in 7.62.0-r0
—
Alpine:v3.15(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.59.0 up to 7.62.0-r0: fixed in 7.62.0-r0
—
Alpine:v3.16(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.59.0 up to 7.62.0-r0: fixed in 7.62.0-r0
—
Alpine:v3.17(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.59.0 up to 7.62.0-r0: fixed in 7.62.0-r0
—
Alpine:v3.18(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.59.0 up to 7.62.0-r0: fixed in 7.62.0-r0
—
Alpine:v3.19(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.59.0 up to 7.62.0-r0: fixed in 7.62.0-r0
—
Alpine:v3.20(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.59.0 up to 7.62.0-r0: fixed in 7.62.0-r0
—
Alpine:v3.21(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.59.0 up to 7.62.0-r0: fixed in 7.62.0-r0
—
Alpine:v3.22(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.59.0 up to 7.62.0-r0: fixed in 7.62.0-r0
—
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.59.0 up to 7.62.0-r0: fixed in 7.62.0-r0
—
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.59.0 up to 7.62.0-r0: fixed in 7.62.0-r0
—
Alpine:v3.5(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.59.0 up to 7.61.1-r1: fixed in 7.61.1-r1
—
Alpine:v3.6(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.59.0 up to 7.61.1-r1: fixed in 7.61.1-r1
—
Alpine:v3.7(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.59.0 up to 7.61.1-r1: fixed in 7.61.1-r1
—
Alpine:v3.8(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.59.0 up to 7.61.1-r1: fixed in 7.61.1-r1
—
Alpine:v3.9(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • 7.59.0 up to 7.62.0-r0: fixed in 7.62.0-r0
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • every version up to 7.62.0-1: fixed in 7.62.0-1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • every version up to 7.62.0-1: fixed in 7.62.0-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • every version up to 7.62.0-1: fixed in 7.62.0-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
curl—
  • every version up to 7.62.0-1: fixed in 7.62.0-1
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(2)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 4× in last 7d / 27× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 163 total refreshes for this CVE.

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Related CVEs(same product + same vendor + same CWE)

Frequently asked(5)

What is CVE-2018-16840?
CVE-2018-16840 is a critical vulnerability published on October 31, 2018. 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…
When was CVE-2018-16840 disclosed?
CVE-2018-16840 was first published on October 31, 2018, with the most recent update on April 17, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2018-16840 actively exploited?
CVE-2018-16840 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 3.4% probability of exploitation in the next 30 days (88th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2018-16840?
CVE-2018-16840 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2018-16840?
A fix for CVE-2018-16840 is available: update to the fixed version the vendor names in its advisory.

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