CVE-2019-14431: In MatrixSSL 3.8.3 Open through 4.2.1 Open, the DTLS server mishandles incoming network messages leading to a

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CRITICAL 9.8REMOTEUPGRADE

CVE-2019-14431 is a critical-severity flaw (CVSS 9.8) affecting matrixssl. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In MatrixSSL 3.8.3 Open through 4.2.1 Open, the DTLS server mishandles incoming network messages leading to a heap-based buffer overflow of up to 256 bytes and possible Remote Code Execution in parseSSLHandshake in sslDecode.c. During processing of a crafted packet, the server mishandles the fragment length value provided in the DTLS message.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

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	3.6% (top 10%)
CISA exploited list	No
Weakness	CWE-755, CWE-787
Published	2019-07-29
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: matrixssl

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

Am I affected?

Timeline

2019-07-29 22:15 UTCPublished CVE record published
2026-06-17 02:18 UTCUpdated Record last modified

matrixssl matrixssl UPGRADE

Affected: >= 3.8.2 and <= 4.2.1

Fixed in: newer than 4.2.1

Safe to downgrade to: a release before 3.8.2

1. Check installed version

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

2. UPGRADE to newer than 4.2.1 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade matrixssl

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 3.8.2 (Debian / Ubuntu)

apt-cache madison matrixssl sudo apt install matrixssl=<VERSION_BEFORE_3.8.2> sudo apt-mark hold matrixssl

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

dnf --showduplicates list matrixssl sudo dnf downgrade matrixssl-<VERSION_BEFORE_3.8.2> sudo dnf versionlock add matrixssl

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.

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-2019-14431?

matrixssl: upgrade to newer than 4.2.1. Exact commands for each OS are on this page.

Is CVE-2019-14431 being exploited?

CVE-2019-14431 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-2019-14431 affect?

CVE-2019-14431 affects matrixssl. Severity is critical (CVSS 9.8). In MatrixSSL 3.8.3 Open through 4.2.1 Open, the DTLS server mishandles incoming network messages leading to a heap-based buffer overflow of up to 256 bytes and possible Remote Code Execution in parseSSLHandshake in sslDecode.c. During proce

How urgent is CVE-2019-14431?

Priority 67/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

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CVE-2022-43974 HIGH 8.1 UPGRADE MatrixSSL 4.0.4 through 4.5.1 has an integer overflow in matrixSslDecodeTls13
CVE-2019-16747 HIGH 7.5 UPGRADE In MatrixSSL before 4.2.2 Open, the DTLS server can encounter an invalid pointer free (leading to memory corru
CVE-2019-13629 MEDIUM 5.9 UPGRADE MatrixSSL 4.2.1 and earlier contains a timing side channel in ECDSA signature generation

References

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