CVE-2017-6419: mspack/lzxd.c in libmspack 0.5alpha, as used in ClamAV 0.99.2, allows remote attackers to cause a denial of se

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HIGH 7.8DOWNGRADE

CVE-2017-6419 is a high-severity flaw (CVSS 7.8) affecting libmspack. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

mspack/lzxd.c in libmspack 0.5alpha, as used in ClamAV 0.99.2, allows remote attackers to cause a denial of service (heap-based buffer overflow and application crash) or possibly have unspecified other impact via a crafted CHM file.

Why this priority

High severity

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	2.0% (top 19%)
CISA exploited list	No
Weakness	CWE-119
Published	2017-08-07
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: libmspack project

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

Am I affected?

Timeline

2017-08-07 03:29 UTCPublished CVE record published
2026-06-17 01:22 UTCUpdated Record last modified

libmspack project libmspack DOWNGRADE

Affected: 0.5 alpha

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.5

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 0.5 (Debian / Ubuntu)

apt-cache madison libmspack sudo apt install libmspack=<VERSION_BEFORE_0.5> sudo apt-mark hold libmspack

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

dnf --showduplicates list libmspack sudo dnf downgrade libmspack-<VERSION_BEFORE_0.5> sudo dnf versionlock add libmspack

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-2017-6419?

libmspack: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2017-6419 being exploited?

CVE-2017-6419 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-2017-6419 affect?

CVE-2017-6419 affects libmspack. Severity is high (CVSS 7.8). mspack/lzxd.c in libmspack 0.5alpha, as used in ClamAV 0.99.2, allows remote attackers to cause a denial of service (heap-based buffer overflow and application crash) or possibly have unspecified other impact via a crafted CHM file.

How urgent is CVE-2017-6419?

Priority 47/100. High severity

Related CVEs

CVE-2019-1010305 MEDIUM 5.5 DOWNGRADE MITIGATE libmspack 0.9.1alpha is affected by: Buffer Overflow
CVE-2018-18586 MEDIUM 5.3 DOWNGRADE chmextract.c in the chmextract sample program, as distributed with libmspack before 0.8alpha, does not protect
CVE-2018-18585 MEDIUM 4.3 DOWNGRADE MITIGATE chmd_read_headers in mspack/chmd.c in libmspack before 0.8alpha accepts a filename that has '\0' as its first
CVE-2018-18584 MEDIUM 6.5 UPGRADE DOWNGRADE In mspack/cab.h in libmspack before 0.8alpha and cabextract before 1.8, the CAB block input buffer is one byte
CVE-2018-14682 HIGH 8.8 DOWNGRADE UPGRADE An issue was discovered in mspack/chmd.c in libmspack before 0.7alpha

References

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