PatchTheCVECVE-2018-25032: zlib before 1.2.12 allows memory corruption when deflating (i.e., when compressing) if the input has many dist
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HIGH 7.5REMOTEWATCHLISTUPGRADEUPGRADEUPGRADE
CVE-2018-25032 is a high-severity flaw (CVSS 7.5) affecting nokogiri, python, zlib. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
zlib before 1.2.12 allows memory corruption when deflating (i.e., when compressing) if the input has many distant matches.
Why this priority
- High severity
- EPSS top 1%: very likely to be exploited
- Public exploit reference
- Remotely exploitable, no login, no user action
- On your watchlist
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.5 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 51.7% (top 1%) |
| CISA exploited list | No |
| Weakness | CWE-787 |
| Published | 2022-03-25 |
| Last modified | 2026-10-14 |
Last updated 2026-10-14 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
nokogiri nokogiri UPGRADE
Affected: < 1.13.4
Fixed in: 1.13.4
Safe to downgrade to: no unaffected older release
1. Check installed version
apt-cache policy nokogiri || rpm -q nokogiri || nokogiri --version
2. UPGRADE to 1.13.4 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade nokogiri
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade nokogiri
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
python python UPGRADE
Affected: >= 3.7.0 and < 3.7.14 · >= 3.8.0 and < 3.8.14 · >= 3.9.0 and < 3.9.13 · >= 3.10.0 and < 3.10.5
Fixed in: 3.7.14, 3.8.14, 3.9.13, 3.10.5
Safe to downgrade to: a release before 3.7.0
1. Check installed version
apt-cache policy python || rpm -q python || python --version
2. UPGRADE to 3.7.14 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade python
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade python
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 3.7.0 (Debian / Ubuntu)
apt-cache madison python
sudo apt install python=<VERSION_BEFORE_3.7.0>
sudo apt-mark hold python
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list python
sudo dnf downgrade python-<VERSION_BEFORE_3.7.0>
sudo dnf versionlock add python
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.
zlib zlib UPGRADE
Affected: >= 1.2.2.2 and < 1.2.12
Fixed in: 1.2.12
Safe to downgrade to: a release before 1.2.2.2
1. Check installed version
apt-cache policy zlib || rpm -q zlib || zlib --version
2. UPGRADE to 1.2.12 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade zlib
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade zlib
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 1.2.2.2 (Debian / Ubuntu)
apt-cache madison zlib
sudo apt install zlib=<VERSION_BEFORE_1.2.2.2>
sudo apt-mark hold zlib
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list zlib
sudo dnf downgrade zlib-<VERSION_BEFORE_1.2.2.2>
sudo dnf versionlock add zlib
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.
debian debian linux MITIGATE
Affected: 9.0 · 10.0 · 11.0
Fixed in: no fixed release known
Safe to downgrade to: a release before 9.0
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.
fedoraproject fedora MITIGATE
Affected: 34 · 35 · 36
Fixed in: no fixed release known
Safe to downgrade to: a release before 34
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.
apple mac os x UPGRADE
Affected: >= 10.15 and < 10.15.7 · 10.15.7 · 10.15.7 security_update_2020 · 10.15.7 security_update_2020-001 · 10.15.7 security_update_2020-005 · 10.15.7 security_update_2020-007 · 10.15.7 security_update_2021-001 · 10.15.7 security_update_2021-002
Fixed in: 10.15.7
Safe to downgrade to: a release before 10.15
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.
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-2018-25032?
nokogiri: upgrade to 1.13.4; python: upgrade to 3.7.14, 3.8.14, 3.9.13, 3.10.5; zlib: upgrade to 1.2.12. Exact commands for each OS are on this page.
Is CVE-2018-25032 being exploited?
CVE-2018-25032 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-2018-25032 affect?
CVE-2018-25032 affects nokogiri, python, zlib. Severity is high (CVSS 7.5). zlib before 1.2.12 allows memory corruption when deflating (i.e., when compressing) if the input has many distant matches.
How urgent is CVE-2018-25032?
Priority 66/100. High severity; EPSS top 1%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist
Software pages
Python vulnerabilities · Debian vulnerabilities · zlib vulnerabilities
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