CVE-2019-17362: In LibTomCrypt through 1.18.2, the der_decode_utf8_string function (in der_decode_utf8_string.c) does not prop

Q: How do I fix CVE-2019-17362?

libtomcrypt: upgrade to newer than 1.18.2; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2019-17362 being exploited?

CVE-2019-17362 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2019-17362 affect?

CVE-2019-17362 affects libtomcrypt, debian linux. Severity is critical (CVSS 9.1). In LibTomCrypt through 1.18.2, the der_decode_utf8_string function (in der_decode_utf8_string.c) does not properly detect certain invalid UTF-8 sequences. This allows context-dependent attackers to cause a denial of service (out-of-bounds r

Q: How urgent is CVE-2019-17362?

Priority 69/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

This week

CRITICAL 9.1REMOTEWATCHLISTUPGRADEMITIGATE

CVE-2019-17362 is a critical-severity flaw (CVSS 9.1) affecting libtomcrypt, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In LibTomCrypt through 1.18.2, the der_decode_utf8_string function (in der_decode_utf8_string.c) does not properly detect certain invalid UTF-8 sequences. This allows context-dependent attackers to cause a denial of service (out-of-bounds read and crash) or read information from other memory locations via carefully crafted DER-encoded data.

Why this priority

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

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	3.1% (top 12%)
CISA exploited list	No
Weakness	CWE-125
Published	2019-10-09
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: debian · libtom

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

Am I affected?

Timeline

2019-10-09 01:15 UTCPublished CVE record published
2026-06-17 02:23 UTCUpdated Record last modified

libtom libtomcrypt UPGRADE

Affected: <= 1.18.2

Fixed in: newer than 1.18.2

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 1.18.2 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade libtomcrypt

Note

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

debian debian linux MITIGATE

Affected: 8.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

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.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

Fedora 46 · libopenmpt · FIXED · 0.8.10-2.fc46 · FEDORA-2026-a9998621be · source

sudo dnf upgrade --advisory=FEDORA-2026-a9998621be

Debian 12 · libtomcrypt · FIXED · 1.18.2-3

sudo apt update && sudo apt install --only-upgrade libtomcrypt dpkg --compare-versions "$(dpkg-query -W -f='${Version}' libtomcrypt)" ge "1.18.2-3" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · libtomcrypt · FIXED · 1.18.2-3

sudo apt update && sudo apt install --only-upgrade libtomcrypt dpkg --compare-versions "$(dpkg-query -W -f='${Version}' libtomcrypt)" ge "1.18.2-3" && echo PATCHED || echo STILL-VULNERABLE

Alpine 3.20 · perl-cryptx · FIXED · perl-cryptx-0.079-r0

apk add --upgrade perl-cryptx apk info -v perl-cryptx

Alpine 3.21 · perl-cryptx · FIXED · perl-cryptx-0.079-r0

apk add --upgrade perl-cryptx apk info -v perl-cryptx

Alpine 3.22 · perl-cryptx · FIXED · perl-cryptx-0.079-r0

apk add --upgrade perl-cryptx apk info -v perl-cryptx

Alpine 3.23 · perl-cryptx · FIXED · perl-cryptx-0.079-r0

apk add --upgrade perl-cryptx apk info -v perl-cryptx

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: github.com/libtom/libtomcrypt/issues/507
Write-up: github.com/libtom/libtomcrypt/pull/508
Write-up: vuldb.com/?id.142995

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-2019-17362?

libtomcrypt: upgrade to newer than 1.18.2; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2019-17362 being exploited?

CVE-2019-17362 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-2019-17362 affect?

CVE-2019-17362 affects libtomcrypt, debian linux. Severity is critical (CVSS 9.1). In LibTomCrypt through 1.18.2, the der_decode_utf8_string function (in der_decode_utf8_string.c) does not properly detect certain invalid UTF-8 sequences. This allows context-dependent attackers to cause a denial of service (out-of-bounds r

How urgent is CVE-2019-17362?

Priority 69/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Debian vulnerabilities

Related CVEs

CVE-2018-12437 MEDIUM 4.9 UPGRADE UPGRADE LibTomCrypt through 1.18.1 allows a memory-cache side-channel attack on ECDSA signatures, aka the Return Of th
CVE-2016-6129 HIGH 7.5 UPGRADE UPGRADE The rsa_verify_hash_ex function in rsa_verify_hash.c in LibTomCrypt, as used in OP-TEE before 2.2.0, does not
CVE-2005-1600 HIGH 7.5 DOWNGRADE A "mathematical flaw" in the implementation of the El Gamal signature algorithm for LibTomCrypt 1.0 to 1.0.2 a

References

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