CVE-2019-1010305: libmspack 0.9.1alpha is affected by: Buffer Overflow

This month

MEDIUM 5.5WATCHLISTDOWNGRADEMITIGATEMITIGATE

CVE-2019-1010305 is a medium-severity flaw (CVSS 5.5) affecting libmspack, fedora, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

libmspack 0.9.1alpha is affected by: Buffer Overflow. The impact is: Information Disclosure. The component is: function chmd_read_headers() in libmspack(file libmspack/mspack/chmd.c). The attack vector is: the victim must open a specially crafted chm file. The fixed version is: after commit 2f084136cfe0d05e5bf5703f3e83c6d955234b4d.

Why this priority

Public exploit reference
On your watchlist

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

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	1.5% (top 26%)
CISA exploited list	No
Weakness	CWE-119
Published	2019-07-15
Last modified	2026-06-17

Publisher (CNA): DWF · Vendor: canonical · debian · fedoraproject · kyzer

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

Am I affected?

Timeline

2019-07-15 15:15 UTCPublished CVE record published
2026-06-17 02:09 UTCUpdated Record last modified

kyzer libmspack DOWNGRADE

Affected: 0.9.1 alpha

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.9.1

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 0.9.1 (Debian / Ubuntu)

apt-cache madison libmspack sudo apt install libmspack=<VERSION_BEFORE_0.9.1> sudo apt-mark hold libmspack

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

dnf --showduplicates list libmspack sudo dnf downgrade libmspack-<VERSION_BEFORE_0.9.1> 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.

fedoraproject fedora MITIGATE

Affected: 29 · 30

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: 8.0 · 9.0

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.

canonical ubuntu linux MITIGATE

Affected: 12.04 · 14.04 · 16.04 · 18.04

Fixed in: no fixed release known

Safe to downgrade to: a release before 12.04

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.

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-2019-1010305?

libmspack: downgrade or apply the listed mitigation; fedora: 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-2019-1010305 being exploited?

CVE-2019-1010305 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-2019-1010305 affect?

CVE-2019-1010305 affects libmspack, fedora, debian linux. Severity is medium (CVSS 5.5). libmspack 0.9.1alpha is affected by: Buffer Overflow. The impact is: Information Disclosure. The component is: function chmd_read_headers() in libmspack(file libmspack/mspack/chmd.c). The attack vector is: the victim must open a specially c

How urgent is CVE-2019-1010305?

Priority 48/100. Public exploit reference; On your watchlist

Software pages

Ubuntu vulnerabilities · Debian vulnerabilities

Related CVEs

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
CVE-2018-14681 HIGH 8.8 DOWNGRADE UPGRADE An issue was discovered in kwajd_read_headers in mspack/kwajd.c in libmspack before 0.7alpha

References

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