CVE-2026-53727

HIGHNVD 8.68.6
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

This high-severity CVE scores 8.6 under NVD CVSS v3. EPSS exploit probability: 0.5% (41st percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, NVD CVSS v3
Elevated
8.6EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 8.6Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

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 v3
8.6
EG Score
8.6HIGHmedium confidence
EG Risk
55
EG Risk 55/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed (value × EchelonGraph’s weight)
Severity86% × 45%
The EG Score, 8.6 of 10.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.5%
EPSS %ILE
41st
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

July 9, 2026

Last Modified

August 18, 2026

Advisory Details (3)

Auto-updated Jul 17, 2026
Patch available. Sources: github_commit, github.
GitHub advisoryMentions a patch (unverified)

SSRF and Local File Disclosure in `CssParser::Parser#read_remote_file` · Advisory · premailer/css_parser · GitHub

https://github.com/premailer/css_parser/security/advisories/GHSA-9pmc-p236-855h
GitHub commit

commit e0a151458b2a (premailer/css_parser)

Fix landed in premailer/css_parser commit e0a151458b2a — awaiting tagged release

https://github.com/premailer/css_parser/commit/e0a151458b2a801ae265ba420862ef8b1127b3ae
GitHub commit

commit 7d2ddf0189cd (premailer/css_parser)

Fix landed in premailer/css_parser commit 7d2ddf0189cd — awaiting tagged release

https://github.com/premailer/css_parser/commit/7d2ddf0189cd54b54f378f59daefa10cb036e476

Vendor Advisories for CVE-2026-53727(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(5 across 5 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
ruby-css-parser1.16.0-1 ... 3.0.0-1 (8 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
ruby-css-parser1.16.0-1 ... 3.1.0-1 (9 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
ruby-css-parser1.19.0-1 ... 3.1.0-1 (7 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
ruby-css-parser1.19.0-1, 1.21.1-1, 2.0.0-1, 2.1.0-1
  • every version up to 3.0.0-1: fixed in 3.0.0-1
—
RubyGems(1)
PackageVulnerable rangeFix by version rangeDependents
css_parser0.9.0 ... 2.2.0 (64 versions)
  • every version up to 3.0.0: fixed in 3.0.0
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 33× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 100 of 131 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 31 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  2. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  3. 2026-10-12 15:57 UTCEG score recompute
  4. 2026-10-11 19:40 UTCEG score recompute
  5. 2026-10-11 16:55 UTCEG score recompute
  6. 2026-10-11 14:18 UTCEG score recompute
  7. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  8. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  9. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  10. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  11. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  12. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  13. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  14. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  15. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  16. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  17. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  18. 2026-10-01 16:03 UTCEG score recompute
  19. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  20. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  21. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  22. 2026-09-28 10:54 UTCEG score recompute
  23. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  24. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  25. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.5% · 40th percentile
Show 75 more
  1. 2026-09-24 11:26 UTCEG score recompute
  2. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  3. 2026-09-23 05:59 UTCEG score recompute
  4. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  5. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  6. 2026-09-18 05:37 UTCEG score recompute
  7. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  8. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  9. 2026-09-13 23:46 UTCEG score recompute
  10. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  11. 2026-09-12 16:41 UTCEG score recompute
  12. 2026-09-12 03:24 UTCEG score recompute
  13. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  14. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  15. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  16. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  17. 2026-09-06 14:00 UTCEG score recompute
  18. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  19. 2026-09-05 22:36 UTCEG score recompute
  20. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  21. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  22. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  23. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  24. 2026-08-30 19:54 UTCEG score recompute
  25. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  26. 2026-08-30 06:56 UTCEG score recompute
  27. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  28. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  29. 2026-08-27 21:46 UTCEG score recompute
  30. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  31. 2026-08-27 01:10 UTCEG score recompute
  32. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  33. 2026-08-26 03:53 UTCEG score recompute
  34. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  35. 2026-08-24 23:11 UTCEG score recompute
  36. 2026-08-24 10:14 UTCEG score recompute
  37. 2026-08-23 08:18 UTCEG score recompute
  38. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  39. 2026-08-22 06:23 UTCEG score recompute
  40. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  41. 2026-08-21 04:16 UTCEG score recompute
  42. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  43. 2026-08-20 01:49 UTCEG score recompute
  44. 2026-08-19 17:04 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  45. 2026-08-18 15:39 UTCEG score recompute▼ 0.30
  46. 2026-08-18 15:39 UTCNVD updateCVSS v3 → 8.6
  47. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  48. 2026-08-18 02:55 UTCEG score recompute
  49. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  50. 2026-08-17 00:05 UTCEG score recompute
  51. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  52. 2026-08-16 11:08 UTCEG score recompute
  53. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  54. 2026-08-15 09:13 UTCEG score recompute
  55. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  56. 2026-08-14 07:18 UTCEG score recompute
  57. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  58. 2026-08-12 16:21 UTCEG score recompute
  59. 2026-08-12 13:51 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  60. 2026-08-11 14:26 UTCEG score recompute
  61. 2026-08-11 01:27 UTCEG score recompute
  62. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  63. 2026-08-09 23:28 UTCEG score recompute
  64. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  65. 2026-08-08 21:34 UTCEG score recompute
  66. 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  67. 2026-08-07 19:40 UTCEG score recompute
  68. 2026-08-06 17:45 UTCEG score recompute
  69. 2026-08-06 13:47 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  70. 2026-08-06 04:47 UTCEG score recompute
  71. 2026-08-05 19:17 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  72. 2026-08-05 02:36 UTCEG score recompute
  73. 2026-08-04 15:10 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  74. 2026-08-04 13:38 UTCEG score recompute
  75. 2026-08-04 10:39 UTCEPSS rescoreEPSS 0.3% · 22nd percentile

Related CVEs(same product + same CWE)

Same product

1 shown

Debian:11:ruby-css-parser

Frequently asked(5)

What is CVE-2026-53727?
CVE-2026-53727 is a high-severity vulnerability; its CVE record was published on July 9, 2026. cssparser is a Ruby CSS parser. From 2.2.0 until 3.0.0, CssParser::Parser#readremotefile in lib/cssparser/parser.rb, and therefore loaduri! and the @import-following branch of addblock!, issued HTTP and HTTPS requests against any host, port, and URI without a scheme allowlist, host or IP filtering,…
When was the CVE record for CVE-2026-53727 published?
The CVE record for CVE-2026-53727 was published on July 9, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of August 18, 2026; the record at its source may have been updated since.
Is CVE-2026-53727 actively exploited?
CVE-2026-53727 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (41st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-53727?
CVE-2026-53727 has a CVSS v3 base score of 8.6 (NVD).
How do I remediate CVE-2026-53727?
A fix for CVE-2026-53727 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-53727 are linked in the Vendor Advisories panel on this page.

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