CVE-2026-4671

HIGHPre-NVD 7.57.5—
EchelonGraph scoreHIGH confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-08-23. a secondary CVSS source baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

justhtml before 1.18.0 contains multiple low-severity denial-of-service issues in CSS selector handling and linkification. Applications that evaluate attacker-controlled selector strings (via query(), matches(), or selector-based transforms), run selector matching over very large untrusted documents, construct DOM trees from untrusted structure, or enable linkification over attacker-controlled text may consume disproportionate CPU or memory. Triggers include oversized selectors, large selector lists, oversized compound selectors, long combinator chains, deeply nested functional pseudo-classes, repeated token/positional matching, cyclic DOM graphs causing non-terminating traversal, and punctuation-heavy or trailing-bracket linkification input. These are availability-only concerns and do not by themselves allow script execution, data disclosure, or sanitizer bypass. Default JustHTML(sanitize=True) usage is not expected to be exposed, since selectors are normally supplied by application code.

CVSS v3
7.5
EG Score
7.5(high)
EG Risk
49(Track)
EG Risk 49/100SSVC: Track

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
Severity75% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
31%
KEV
Not listed

Published

August 23, 2026

Last Modified

August 26, 2026

Advisory Details (2)

Auto-updated Aug 23, 2026
Patch available. Sources: github.
generic

justhtml before 1.18.0 Denial of Service via CSS Selector | Advisories | VulnCheck

https://www.vulncheck.com/advisories/justhtml-before-denial-of-service-via-css-selector
github Patch Available

Denial-of-service hardening in justhtml 1.18.0 · Advisory · EmilStenstrom/justhtml · GitHub

https://github.com/EmilStenstrom/justhtml/security/advisories/GHSA-r8cj-3554-33mr

Vendor Advisories for CVE-2026-4671(1)

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

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
justhtml0.1.0 ... 1.9.1 (62 versions)1.18.0—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 23× in last 7d / 108× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

Showing the most recent 100 of 108 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-4671?
CVE-2026-4671 is a high vulnerability published on August 23, 2026. justhtml before 1.18.0 contains multiple low-severity denial-of-service issues in CSS selector handling and linkification. Applications that evaluate attacker-controlled selector strings (via query(), matches(), or selector-based transforms), run selector matching over very large untrusted…
When was CVE-2026-4671 disclosed?
CVE-2026-4671 was first published in the National Vulnerability Database on August 23, 2026, with the most recent update on August 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-4671 actively exploited?
CVE-2026-4671 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 68.9% of all scored CVEs.
What is the CVSS score of CVE-2026-4671?
CVE-2026-4671 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-4671?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-4671, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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