CVE catalog
CVE-2026-53727
css_parser is a Ruby CSS parser. From 2.2.0 until 3.0.0, CssParser::Parser#read_remote_file in lib/css_parser/parser.rb, and therefore load_uri! and the @import-following branch of add_block!, issued
- Severity
- High · CVSS 8.9
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.51% · Oct 25, 2026
css_parser is a Ruby CSS parser. From 2.2.0 until 3.0.0, CssParser::Parser#read_remote_file in lib/css_parser/parser.rb, and therefore load_uri! and the @import-following branch of add_block!, issued HTTP and HTTPS requests against any host, port, and URI without a scheme allowlist, host or IP filtering, or protection against link-local, loopback, or RFC-1918 addresses. Location: redirects were followed recursively back into the same function, which also serviced file:// URIs, so a single attacker-controlled HTTP redirect could upgrade the bug from SSRF to arbitrary local file disclosure. Any consumer of css_parser that hands it attacker-influenced CSS together with a base_uri: option is exposed. This issue is fixed in version 3.0.0.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | ruby-css-parser | sid | 3.3.0-1 | fixed |
| Debian | ruby-css-parser | forky | 3.3.0-1 | fixed |
| Debian | ruby-css-parser | trixie | 1.19.0-1+deb13u1 | vulnerable |
| Debian | ruby-css-parser | bookworm | 1.6.0-2+deb12u1 | vulnerable |
| Cpe | ruby-css-parser | Not reported | Not reported | vulnerable |
| Cpe | css_parser | Not reported | Not reported | unknown |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | ruby-css-parser | source | sid | 3.0.0-1 | not yet assigned | Not reported | Not reported |
| Debian | ruby-css-parser | source | forky | 3.0.0-1 | not yet assigned | Not reported | Not reported |
| Debian | ruby-css-parser | source | trixie | (unfixed) | not yet assigned | Not reported | Not reported |
| Debian | ruby-css-parser | source | bookworm | (unfixed) | not yet assigned | Not reported | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [ruby-css-parser]Affected
Details (2)
1.6.0-2+deb12u1· all · bookwormAffected
nvd · ruby-css-parser · debian · bookworm; nvd · ruby-css-parser · debian · 12
1.6.0-2+deb12u1· all · bookwormAffected
nvd · ruby-css-parser · debian · bookworm; nvd · ruby-css-parser · debian · 12
[Debian 13 (Trixie)]
- [ruby-css-parser]Affected
Details (2)
1.19.0-1+deb13u1· all · trixieAffected
nvd · ruby-css-parser · debian · 13
1.19.0-1+deb13u1· all · trixieAffected
nvd · ruby-css-parser · debian · 13
Observed:
References
- [https://github.com/premailer/css_parser/commit/7d2ddf0189cd54b54f378f59daefa10cb036e476]
- [https://github.com/premailer/css_parser/commit/e0a151458b2a801ae265ba420862ef8b1127b3ae]
- [https://github.com/premailer/css_parser/releases/tag/v3.0.0]
- [https://github.com/premailer/css_parser/security/advisories/GHSA-9pmc-p236-855h]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-53727]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-53727]
- [https://security-tracker.debian.org/tracker/CVE-2026-53727]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53727.json]
[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX]