Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
premailer css_parser — css_parser: SSRF and Local File Disclosure in `CssParser::Parser#read_remote_file`
AV AC AT PR UI VC VI VA CVSS EPSS %ile KEV
N L P N N H N N 8.9 .0037 29.7 —
AFFECTED
Product Versions Fixed
css_parser < 3.0.0 – —
TIMELINE
Jun 10 Reserved by GitHub_M
Jul 17 EXPLOIT PUBLISHED — CVE-2026-53727 (premailer css_parser). Public exploit reference added.
Jul 17 Published (CNA: GitHub_M)
Description
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.
Lifecycle
Complete event history — 3 events, chronological
| Date | Event | Detail |
|---|
| June 10, 2026 | Reserved | Reserved by GitHub_M |
| July 17, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-53727 (premailer css_parser). Public exploit reference added. |
| July 17, 2026 | Published | Published (CNA: GitHub_M) |
Affected
Affected products and packages — 1 row
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|
| premailer | css_parser | — | < 3.0.0 | — |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-53727 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.