CVE-2026-69153: PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an

This week

MEDIUM 5.3REMOTEUPGRADE

CVE-2026-69153 is a medium-severity flaw (CVSS 5.3) affecting postcss. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. Prior to 8.5.19, if from is unset, an attacker can cause PreviousMap.loadFile() to read an unintended source-map file by supplying an absolute or directory-traversal sourceMappingURL. The resulting map’s sources and sourcesContent may then be exposed to the application. This issue is fixed in version 8.5.19.

Why this priority

Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 61%)
CISA exploited list	No
Weakness	CWE-22, CWE-200
Published	2026-08-03
Last modified	2026-08-05

Publisher (CNA): GitHub, Inc. · Vendor: postcss

Last updated 2026-08-05 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-08-03 17:16 UTCPublished CVE record published
2026-08-05 14:58 UTCUpdated Record last modified

postcss postcss UPGRADE

Affected: < 8.5.23

Fixed in: 8.5.23

Safe to downgrade to: no unaffected older release

1. Check installed version

npm ls postcss

2. UPGRADE to 8.5.23

npm install postcss@">=8.5.23"

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-2026-69153?

postcss: upgrade to 8.5.23. Exact commands for each OS are on this page.

Is CVE-2026-69153 being exploited?

CVE-2026-69153 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-2026-69153 affect?

CVE-2026-69153 affects postcss. Severity is medium (CVSS 5.3). PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. Prior to 8.5.19, if from is unset, an attacker can cause PreviousMap.loadFile() to read an unintended sourc

How urgent is CVE-2026-69153?

Priority 38/100. Public exploit reference; Remotely exploitable, no login, no user action

References

← Back to latest CVEs