What is CVE-2018-25032?A high-severity flaw in Zlib, explained.
CVE-2018-25032 is a high-severity flaw (CVSS 7.5) in Zlib, published on 25 March 2022. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 52%. If you run an affected version, plan in the vendor’s fix.
Published 25 March 2022. Record last updated 6 May 2025. We keep this page's data up to date.
What is CVE-2018-25032? In plain terms.
It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can take it offline.
zlib before 1.2.12 allows memory corruption when deflating (i.e., when compressing) if the input has many distant matches.
What kind of flaw is it?
- CWE-787Out-of-bounds Write
How an attack on it works
Read straight from its severity rating, translated out of the shorthand.
- Where an attacker can beAnywhere on the internet
- How hard it is to pull offEasy: no special conditions
- Login needed firstNo login needed
- Does someone have to clickNo, nobody has to do anything
- What an attacker getsCan take it offline
Severity vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Is CVE-2018-25032 being exploited? Not that we know of.
It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 52%. That can change at any time, which is why we keep watching.
Timeline
- Published
- Record last updated
- Exploit likelihood jumped
- Exploit likelihood fell
CVE-2018-25032 scores 56. Action: Plan remediation.
We keep the score of every published flaw up to date as the evidence changes. Four things go into the score, and evidence that criminals are actually using it counts most. In order:
- Evidence it is being exploitedBiggest factor
- How severe it isStrong factor
- How widely exposed it isSmaller factor
- Threat activity around itSmaller factor
85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score.
When CVE-2018-25032 matches software you track, it lands in your list with its score and the reasons behind it.
See your own ranked list →Who is affected by CVE-2018-25032? 38 products.
The published record lists 38 products from 11 vendors. Versions are shown as published: "before 1.2.12" means every version up to, but not including, 1.2.12. If you run one of these, check your version, then go to the fix below.
- Application
Zlib
by Zlib
Affected versionsbefore 1.2.12 - Operating system
Mac OS X
by Apple
Affected versions10.15 to before 10.15.710.15.710.15.7-security_update_202010.15.7-security_update_2020-00110.15.7-security_update_2020-00510.15.7-security_update_2020-007 - Application
Mariadb
by Mariadb
Affected versions10.3.0 to before 10.3.3610.4.0 to before 10.4.2610.5.0 to before 10.5.1710.6.0 to before 10.6.910.7.0 to before 10.7.510.8.0 to before 10.8.4 - Application
Zulu
by Azul
Affected versions6.457.528.6011.5413.4615.38 - Application
Python
by Python
Affected versions3.7.0 to before 3.7.143.8.0 to before 3.8.143.9.0 to before 3.9.133.10.0 to before 3.10.5 - Operating system
Debian Linux
by Debian
Affected versions9.010.011.0 - Operating system
Fedora
Affected versions343536 - Operating system
macOS
by Apple
Affected versions11.0 to before 11.6.612.0.0 to before 12.4 - Application
Active Iq Unified Manager
by Netapp
Affected versionsversion not specified
How do I fix CVE-2018-25032? Four steps.
- Check whether you run itCompare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list.
- Apply the vendor’s fixInstall the update named in the vendor’s advisory. We’ve put the advisories and patch notes first in the list.
- If you can’t patch todayFollow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in.
- Keep an eye on itTrack the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood.
Does CVE-2018-25032 affect you? We'll keep checking.
Looking flaws up one at a time doesn't scale. Tell us what you run once, and we tell you which flaws matter to you, in what order, and keep watching for new ones.
- Tell us what you runPick your software from a list, or let us work it out from your website.
- We match it to every flawOver 400,000 published flaws, checked against your list.
- Ranked by real-world riskA 0 to 100 score, led by evidence criminals are using it.
- Told as soon as we knowAn alert by email, in the app or by webhook to your own tools.
Free plan, no card needed. Nothing to install.
1 new flaw affects software Acme tracks
zlib before 1.2.12 allows memory corruption when deflating (i.e., when compressing) if the input has many distant matches.
- Matched to
- Zlib on Acme's software list
- What to do
- Plan in the vendor’s update
Sent to the alert recipients Acme chose. Also in the app and to Acme's webhook.
CVE-2018-25032 is a high-severity flaw in Zlib, published on 25 March 2022. It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can take it offline.
It scores 7.5 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2018-25032 is 56 out of 100, which is Medium. Its action is "Plan remediation". Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month.
It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 52%. That can change at any time, which is why we keep watching.
For Zlib: before 1.2.12. The record lists 38 products in all, each with its versions, under "Who is affected" on this page.
Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet.