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CVE-2018-1000808: Python Cryptographic Authority pyopenssl version Before 17.5.0 contains a CWE - 401 : Failure to Release Memor

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This month
MEDIUM 5.9REMOTEWATCHLISTUPGRADEMITIGATEDOWNGRADE

CVE-2018-1000808 is a medium-severity flaw (CVSS 5.9) affecting pyopenssl, ubuntu linux, gluster storage. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Python Cryptographic Authority pyopenssl version Before 17.5.0 contains a CWE - 401 : Failure to Release Memory Before Removing Last Reference vulnerability in PKCS #12 Store that can result in Denial of service if memory runs low or is exhausted. This attack appear to be exploitable via Depends upon calling application, however it could be as simple as initiating a TLS connection. Anything that would cause the calling application to reload certi

Why this priority

  • Remotely exploitable, no login, no user action
  • On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score5.9 (Medium)
Attack vectorNetwork (remote)
Attack complexityHigh
Privileges neededNone
User interactionNone
EPSS exploit chance1.9% (top 20%)
CISA exploited listNo
WeaknessCWE-404
Published2018-10-08
Last modified2026-06-17
Publisher (CNA): MITRE · Vendor: canonical · pyopenssl project · redhat

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

Am I affected?

Timeline

pyopenssl project pyopenssl UPGRADE
Affected: < 17.5.0
Fixed in: 17.5.0
Safe to downgrade to: no unaffected older release
1. Check installed version
apt-cache policy pyopenssl || rpm -q pyopenssl || pyopenssl --version
2. UPGRADE to 17.5.0 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade pyopenssl
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade pyopenssl
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
canonical ubuntu linux MITIGATE
Affected: 16.04
Fixed in: no fixed release known
Safe to downgrade to: a release before 16.04
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.
redhat gluster storage DOWNGRADE
Affected: 3.0
Fixed in: no fixed release known
Safe to downgrade to: a release before 3.0
1. Check installed version
apt-cache policy gluster-storage || rpm -q gluster-storage || gluster-storage --version
2. No fixed release: DOWNGRADE to a release before 3.0 (Debian / Ubuntu)
apt-cache madison gluster-storage sudo apt install gluster-storage=<VERSION_BEFORE_3.0> sudo apt-mark hold gluster-storage
2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list gluster-storage sudo dnf downgrade gluster-storage-<VERSION_BEFORE_3.0> sudo dnf versionlock add gluster-storage
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.
redhat openstack DOWNGRADE
Affected: 13
Fixed in: no fixed release known
Safe to downgrade to: a release before 13
1. Check installed version
apt-cache policy openstack || rpm -q openstack || openstack --version
2. No fixed release: DOWNGRADE to a release before 13 (Debian / Ubuntu)
apt-cache madison openstack sudo apt install openstack=<VERSION_BEFORE_13> sudo apt-mark hold openstack
2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list openstack sudo dnf downgrade openstack-<VERSION_BEFORE_13> sudo dnf versionlock add openstack
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.
redhat enterprise linux desktop MITIGATE
Affected: 7.0
Fixed in: no fixed release known
Safe to downgrade to: a release before 7.0
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.
redhat enterprise linux server MITIGATE
Affected: 7.0
Fixed in: no fixed release known
Safe to downgrade to: a release before 7.0
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.
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-2018-1000808?

pyopenssl: upgrade to 17.5.0; ubuntu linux: mitigate or apply the listed mitigation; gluster storage: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2018-1000808 being exploited?

CVE-2018-1000808 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-2018-1000808 affect?

CVE-2018-1000808 affects pyopenssl, ubuntu linux, gluster storage. Severity is medium (CVSS 5.9). Python Cryptographic Authority pyopenssl version Before 17.5.0 contains a CWE - 401 : Failure to Release Memory Before Removing Last Reference vulnerability in PKCS #12 Store that can result in Denial of service if memory runs low or is exh

How urgent is CVE-2018-1000808?

Priority 51/100. Remotely exploitable, no login, no user action; On your watchlist

Software pages

Python vulnerabilities · Ubuntu vulnerabilities · OpenStack vulnerabilities

Related CVEs

References

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