CVE-2019-3822: libcurl versions from 7.36.0 to before 7.64.0 are vulnerable to a stack-based buffer overflow

This week

CRITICAL 9.8REMOTEWATCHLISTUPGRADEMITIGATEMITIGATE

CVE-2019-3822 is a critical-severity flaw (CVSS 9.8) affecting libcurl, ubuntu linux, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

libcurl versions from 7.36.0 to before 7.64.0 are vulnerable to a stack-based buffer overflow. The function creating an outgoing NTLM type-3 header (`lib/vauth/ntlm.c:Curl_auth_create_ntlm_type3_message()`), generates the request HTTP header contents based on previously received data. The check that exists to prevent the local buffer from getting overflowed is implemented wrongly (using unsigned math) and as such it does not prevent the overflow

Why this priority

Critical severity
EPSS top 4%: very likely to be exploited
Public exploit reference
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	12.9% (top 4%)
CISA exploited list	No
Weakness	CWE-121, CWE-787
Published	2019-02-06
Last modified	2026-06-17

Publisher (CNA): Red Hat, Inc. · Vendor: canonical · debian · haxx · netapp

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2019-02-06 20:29 UTCPublished CVE record published
2026-06-17 02:35 UTCUpdated Record last modified

haxx libcurl UPGRADE

Affected: >= 7.36.0 and < 7.64.0

Fixed in: 7.64.0

Safe to downgrade to: a release before 7.36.0

1. Check installed version

apt-cache policy libcurl || rpm -q libcurl || libcurl --version

2. UPGRADE to 7.64.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade libcurl

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade libcurl

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 7.36.0 (Debian / Ubuntu)

apt-cache madison libcurl sudo apt install libcurl=<VERSION_BEFORE_7.36.0> sudo apt-mark hold libcurl

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list libcurl sudo dnf downgrade libcurl-<VERSION_BEFORE_7.36.0> sudo dnf versionlock add libcurl

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

canonical ubuntu linux MITIGATE

Affected: 14.04 · 16.04 · 18.04 · 18.10

Fixed in: no fixed release known

Safe to downgrade to: a release before 14.04

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

debian debian linux MITIGATE

Affected: 9.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

netapp active iq unified manager DOWNGRADE

Affected: >= 7.3

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.3

1. Check installed version

apt-cache policy active-iq-unified-manager || rpm -q active-iq-unified-manager || active-iq-unified-manager --version

2. No fixed release: DOWNGRADE to a release before 7.3 (Debian / Ubuntu)

apt-cache madison active-iq-unified-manager sudo apt install active-iq-unified-manager=<VERSION_BEFORE_7.3> sudo apt-mark hold active-iq-unified-manager

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list active-iq-unified-manager sudo dnf downgrade active-iq-unified-manager-<VERSION_BEFORE_7.3> sudo dnf versionlock add active-iq-unified-manager

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

netapp active iq unified manager DOWNGRADE

Affected: >= 9.5

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.5

1. Check installed version

apt-cache policy active-iq-unified-manager || rpm -q active-iq-unified-manager || active-iq-unified-manager --version

2. No fixed release: DOWNGRADE to a release before 9.5 (Debian / Ubuntu)

apt-cache madison active-iq-unified-manager sudo apt install active-iq-unified-manager=<VERSION_BEFORE_9.5> sudo apt-mark hold active-iq-unified-manager

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list active-iq-unified-manager sudo dnf downgrade active-iq-unified-manager-<VERSION_BEFORE_9.5> sudo dnf versionlock add active-iq-unified-manager

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

netapp clustered data ontap MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy clustered-data-ontap || rpm -q clustered-data-ontap || clustered-data-ontap --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

Fedora 46 · copyparty · FIXED · 1.20.26-1.fc46 · FEDORA-2026-8fbe18458e · source

sudo dnf upgrade --advisory=FEDORA-2026-8fbe18458e

Fedora ELN · man-pages · FIXED · 6.20-1.eln159 · FEDORA-2026-f1f5fb11b4 · source

sudo dnf upgrade --advisory=FEDORA-2026-f1f5fb11b4

Debian 12 · curl · FIXED · 7.64.0-1

sudo apt update && sudo apt install --only-upgrade curl dpkg --compare-versions "$(dpkg-query -W -f='${Version}' curl)" ge "7.64.0-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · curl · FIXED · 7.64.0-1

sudo apt update && sudo apt install --only-upgrade curl dpkg --compare-versions "$(dpkg-query -W -f='${Version}' curl)" ge "7.64.0-1" && echo PATCHED || echo STILL-VULNERABLE

RHEL 8 · curl · FIXED · curl-7.61.1-11.el8

sudo dnf upgrade --advisory=RHSA-2019:3701 rpm -q curl

RHEL 5 · curl · NOT AFFECTED

RHEL 6 · curl · NOT AFFECTED

RHEL 7 · curl · NOT AFFECTED

Alpine 3.20 · curl · FIXED · curl-7.64.0-r0

apk add --upgrade curl apk info -v curl

Alpine 3.21 · curl · FIXED · curl-7.64.0-r0

apk add --upgrade curl apk info -v curl

Alpine 3.22 · curl · FIXED · curl-7.64.0-r0

apk add --upgrade curl apk info -v curl

Alpine 3.23 · curl · FIXED · curl-7.64.0-r0

apk add --upgrade curl apk info -v curl

Amazon Linux 2 · see advisory · FIXED · ALAS2-2019-1162 · source

sudo yum update --advisory=ALAS2-2019-1162

Amazon Linux 1 · see advisory · FIXED · ALAS-2019-1297 · source

sudo yum update --advisory=ALAS-2019-1297

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Write-up: www.oracle.com/technetwork/security-advisory/cpuapr2019-5072813.html
Write-up: www.oracle.com/technetwork/security-advisory/cpujul2019-5072835.html

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2019-3822?

libcurl: upgrade to 7.64.0; ubuntu linux: mitigate or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2019-3822 being exploited?

CVE-2019-3822 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2019-3822 affect?

CVE-2019-3822 affects libcurl, ubuntu linux, debian linux. Severity is critical (CVSS 9.8). libcurl versions from 7.36.0 to before 7.64.0 are vulnerable to a stack-based buffer overflow. The function creating an outgoing NTLM type-3 header (`lib/vauth/ntlm.c:Curl_auth_create_ntlm_type3_message()`), generates the request HTTP heade

How urgent is CVE-2019-3822?

Priority 73/100. Critical severity; EPSS top 4%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Ubuntu vulnerabilities · Debian vulnerabilities · curl vulnerabilities

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References

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