PatchTheCVECVE-2019-5436: A heap buffer overflow in the TFTP receiving code allows for DoS or arbitrary code execution in libcurl versio
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HIGH 7.8WATCHLISTUPGRADEMITIGATEMITIGATE
CVE-2019-5436 is a high-severity flaw (CVSS 7.8) affecting libcurl, leap, fedora. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
A heap buffer overflow in the TFTP receiving code allows for DoS or arbitrary code execution in libcurl versions 7.19.4 through 7.64.1.
Why this priority
- High severity
- EPSS top 1%: very likely to be exploited
- Public exploit reference
- On your watchlist
A fixed release or distro patch exists.
Last updated 2026-10-14 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
haxx libcurl UPGRADE
Affected: >= 7.19.4 and <= 7.64.1
Fixed in: newer than 7.64.1
Safe to downgrade to: a release before 7.19.4
1. Check installed version
apt-cache policy libcurl || rpm -q libcurl || libcurl --version
2. UPGRADE to newer than 7.64.1 (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 7.19.4 (Debian / Ubuntu)
apt-cache madison libcurl
sudo apt install libcurl=<VERSION_BEFORE_7.19.4>
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_7.19.4>
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.
opensuse leap MITIGATE
Affected: 15.0 · 15.1 · 42.3
Fixed in: no fixed release known
Safe to downgrade to: a release before 15.0
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.
fedoraproject fedora MITIGATE
Affected: 29
Fixed in: no fixed release known
Safe to downgrade to: a release before 29
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 · 10.0
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.
f5 traffix signaling delivery controller UPGRADE
Affected: >= 5.0.0 and <= 5.1.0
Fixed in: newer than 5.1.0
Safe to downgrade to: a release before 5.0.0
1. Check installed version
apt-cache policy traffix-signaling-delivery-controller || rpm -q traffix-signaling-delivery-controller || traffix-signaling-delivery-controller --version
2. UPGRADE to newer than 5.1.0 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade traffix-signaling-delivery-controller
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade traffix-signaling-delivery-controller
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 5.0.0 (Debian / Ubuntu)
apt-cache madison traffix-signaling-delivery-controller
sudo apt install traffix-signaling-delivery-controller=<VERSION_BEFORE_5.0.0>
sudo apt-mark hold traffix-signaling-delivery-controller
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list traffix-signaling-delivery-controller
sudo dnf downgrade traffix-signaling-delivery-controller-<VERSION_BEFORE_5.0.0>
sudo dnf versionlock add traffix-signaling-delivery-controller
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 hci management node 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 hci-management-node || rpm -q hci-management-node || hci-management-node --version
No fixed or unaffected release known
Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.
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.
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-2019-5436?
libcurl: upgrade to newer than 7.64.1; leap: mitigate or apply the listed mitigation; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2019-5436 being exploited?
CVE-2019-5436 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-2019-5436 affect?
CVE-2019-5436 affects libcurl, leap, fedora. Severity is high (CVSS 7.8). A heap buffer overflow in the TFTP receiving code allows for DoS or arbitrary code execution in libcurl versions 7.19.4 through 7.64.1.
How urgent is CVE-2019-5436?
Priority 62/100. High severity; EPSS top 1%: very likely to be exploited; Public exploit reference; On your watchlist
Software pages
Debian vulnerabilities · F5 BIG-IP vulnerabilities · curl vulnerabilities
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