CVE-2026-53727css_parser is a Ruby CSS parser.
Updated under an hour ago ()
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It affects premailer css_parser. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 8.6 HIGH (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
- Weakness (CWE)
- CWE-918
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Analyzed
- Record last updated
- Aug 18, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
premailer css_parser premailer:css_parser | 2.2.0 | NVD |
References
- https://github.com/premailer/css_parser/commit/7d2ddf0189cd54b54f378f59daefa10cb036e476patch
- https://github.com/premailer/css_parser/commit/e0a151458b2a801ae265ba420862ef8b1127b3aepatch
- https://github.com/premailer/css_parser/releases/tag/v3.0.0product
- https://github.com/premailer/css_parser/security/advisories/GHSA-9pmc-p236-855hexploit, mitigation, vendor-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.