CVE-2026-75834

MEDIUMPre-NVD 5.45.4—
EchelonGraph scoreMEDIUM confidence

Score 5.4 from GitHub Security Advisory published 2026-08-18. A secondary CVSS source baseline 5.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
5.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 5.4Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Grav before 2.0.14 contains a stored cross-site scripting vulnerability in the Security::detectXss() function (system/src/Grav/Common/Security.php). All XSS detection patterns use the PCRE /u (UTF-8) modifier, so a single invalid UTF-8 byte anywhere in page content causes preg_match() to return false for every pattern, silently bypassing the save-time XSS safety gate (Validation::checkSafety()). An authenticated attacker with page-edit permissions (without the security.xss_whitelist privilege) can store malicious JavaScript that executes in the browser of a visitor who views the affected page.

CVSS v3
5.4
EG Score
5.4MEDIUMmedium confidence
EG Risk
24
EG Risk 24/100CISA 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
Severity54% × 45%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.3%
EPSS %ILE
15th
KEV
Not listed

CISA SSVCTrack at every mission impact level.

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

Exploitation none (CISA Vulnrichment) · Automatable no (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 18, 2026

Last Modified

September 8, 2026

Advisory Details (2)

Auto-updated Aug 18, 2026
Patch available. Sources: github.
generic

Grav before 2.0.14 Stored XSS via Invalid UTF-8 Byte | Advisories | VulnCheck

https://www.vulncheck.com/advisories/grav-before-stored-xss-via-invalid-utf-8-byte
github Patch Available

Single invalid UTF-8 byte disables every rule in Security::detectXss(), bypassing the page-content XSS safety gate · Advisory · getgrav/grav · GitHub

https://github.com/getgrav/grav/security/advisories/GHSA-q2j8-x8hf-63ch

Vendor Advisories for CVE-2026-75834(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)
Packagist(1)
PackageVulnerable rangeFix by version rangeDependents
getgrav/grav0.8.0 ... 2.0.9 (348 versions)
  • every version up to 2.0.14: fixed in 2.0.14
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 56× 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 114 total refreshes for this CVE.

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

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-75834?
CVE-2026-75834 is a medium vulnerability published on August 18, 2026. Grav before 2.0.14 contains a stored cross-site scripting vulnerability in the Security::detectXss() function (system/src/Grav/Common/Security.php). All XSS detection patterns use the PCRE /u (UTF-8) modifier, so a single invalid UTF-8 byte anywhere in page content causes pregmatch() to return…
When was CVE-2026-75834 disclosed?
CVE-2026-75834 was first published on August 18, 2026, with the most recent update on September 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-75834 actively exploited?
CVE-2026-75834 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (15th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-75834?
CVE-2026-75834 has a CVSS base score of 5.4 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-75834?
A fix for CVE-2026-75834 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-75834 are linked in the Vendor Advisories panel on this page.

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