CVE-2026-4671

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM 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: 0.7%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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
7.5HIGHmedium confidence
EG Risk
49
EG Risk 49/100CISA SSVC

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%
Exploitation1% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.7%
EPSS %ILE
49th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

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
githubMentions a patch (unverified)

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 rangeFix by version rangeDependents
justhtml0.1.0 ... 1.9.1 (62 versions)
  • every version up to 1.18.0: fixed in 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 / 104× 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 181 total refreshes for this CVE.

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

Related CVEs(same product + same CWE)

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 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 0.7% probability of exploitation in the next 30 days (49th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-4671?
CVE-2026-4671 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-4671?
A fix for CVE-2026-4671 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-4671 are linked in the Vendor Advisories panel on this page.

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