CVE-2026-87929

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreHIGH confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-09-09. a secondary CVSS source baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.8Exploit: Elevated riskExposed: 0

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

MaxSite CMS through 109.6 ships with a hardcoded session encryption key in application/config/config.php that is never changed during installation, allowing unauthenticated attackers to forge administrator session cookies. Attackers can mint a malicious ci_session cookie with administrator privileges by computing an HMAC-SHA1 using the publicly known encryption key, bypassing authentication checks in is_login() and mso_check_allow() functions.

CVSS v3
9.8
EG Score
9.8(high)
EG Risk
75(Attend)
EG Risk 75/100SSVC: Attend

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
Severity98% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
22%
KEV
Not listed

Published

September 9, 2026

Last Modified

September 14, 2026

Advisory Details (5)

Auto-updated Sep 14, 2026
No patch confirmed yet.
generic

MaxSite CMS through 109.6 Authentication Bypass via Hardcoded Encryption Key | Advisories | VulnCheck

https://www.vulncheck.com/advisories/maxsite-cms-through-109.6-authentication-bypass-via-hardcoded-encryption-key
generic

cms/application/maxsite/common/core/init.php at 2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c · maxsite/cms · GitHub

https://github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/application/maxsite/common/core/init.php#L70-L96
generic

cms/application/config/config.php at 2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c · maxsite/cms · GitHub

https://github.com/maxsite/cms/blob/2ca0a0c7d1d71106a25dbb0f2aedaaefbf12802c/application/config/config.php#L230-L254
generic

GitHub - maxsite/cms: MaxSite CMS. Free CMS for your website. Smart alternative to WordPress · GitHub

https://github.com/maxsite/cms
generic

maxsite-cve4/2026.09.08-maxsite-cms-hardcoded-session-key-auth-bypass.md at main · EviL0rd/maxsite-cve4 · GitHub

https://github.com/EviL0rd/maxsite-cve4/blob/main/2026.09.08-maxsite-cms-hardcoded-session-key-auth-bypass.md

Vendor Advisories for CVE-2026-87929(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 59× in last 7d / 87× 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.

  1. 2026-09-19 17:45 UTCEG score recompute
  2. 2026-09-19 17:45 UTCGHSA enrichment
  3. 2026-09-19 13:45 UTCGHSA enrichment
  4. 2026-09-19 09:45 UTCGHSA enrichment
  5. 2026-09-19 05:19 UTCGHSA enrichment
  6. 2026-09-19 01:19 UTCGHSA enrichment
  7. 2026-09-18 21:19 UTCEG score recompute
  8. 2026-09-18 21:19 UTCGHSA enrichment
  9. 2026-09-18 19:28 UTCEPSS rescore
  10. 2026-09-18 16:16 UTCGHSA enrichment
  11. 2026-09-18 12:15 UTCGHSA enrichment
  12. 2026-09-18 08:14 UTCGHSA enrichment
  13. 2026-09-18 04:14 UTCGHSA enrichment
  14. 2026-09-18 00:14 UTCGHSA enrichment
  15. 2026-09-17 20:14 UTCEG score recompute
  16. 2026-09-17 20:14 UTCGHSA enrichment
  17. 2026-09-17 19:32 UTCEPSS rescore
  18. 2026-09-17 15:41 UTCGHSA enrichment
  19. 2026-09-17 11:40 UTCGHSA enrichment
  20. 2026-09-17 07:39 UTCGHSA enrichment
  21. 2026-09-17 03:38 UTCGHSA enrichment
  22. 2026-09-16 23:38 UTCGHSA enrichment
  23. 2026-09-16 19:37 UTCGHSA enrichment
  24. 2026-09-16 15:35 UTCEG score recompute
  25. 2026-09-16 15:35 UTCGHSA enrichment
Show 62 more
  1. 2026-09-16 14:09 UTCEPSS rescore
  2. 2026-09-16 11:20 UTCGHSA enrichment
  3. 2026-09-16 07:20 UTCEG score recompute
  4. 2026-09-16 07:20 UTCGHSA enrichment
  5. 2026-09-16 05:15 UTCEPSS rescore
  6. 2026-09-16 03:19 UTCGHSA enrichment
  7. 2026-09-15 23:18 UTCGHSA enrichment
  8. 2026-09-15 18:46 UTCGHSA enrichment
  9. 2026-09-15 14:46 UTCGHSA enrichment
  10. 2026-09-15 10:46 UTCGHSA enrichment
  11. 2026-09-15 06:40 UTCEG score recompute
  12. 2026-09-15 06:40 UTCGHSA enrichment
  13. 2026-09-15 03:12 UTCEPSS rescore
  14. 2026-09-15 02:38 UTCGHSA enrichment
  15. 2026-09-14 22:38 UTCGHSA enrichment
  16. 2026-09-14 18:38 UTCEG score recompute
  17. 2026-09-14 18:38 UTCGHSA enrichment
  18. 2026-09-14 14:31 UTCEG score recompute
  19. 2026-09-14 14:31 UTCGHSA enrichment
  20. 2026-09-14 13:50 UTCEG score recompute
  21. 2026-09-14 13:50 UTCGHSA enrichment
  22. 2026-09-14 12:52 UTCGHSA enrichment
  23. 2026-09-14 08:52 UTCGHSA enrichment
  24. 2026-09-14 04:51 UTCGHSA enrichment
  25. 2026-09-14 00:51 UTCGHSA enrichment
  26. 2026-09-13 20:51 UTCGHSA enrichment
  27. 2026-09-13 16:51 UTCEG score recompute
  28. 2026-09-13 16:51 UTCGHSA enrichment
  29. 2026-09-13 16:48 UTCEPSS rescore
  30. 2026-09-13 12:51 UTCGHSA enrichment
  31. 2026-09-13 08:50 UTCGHSA enrichment
  32. 2026-09-13 04:50 UTCGHSA enrichment
  33. 2026-09-13 00:50 UTCGHSA enrichment
  34. 2026-09-12 20:49 UTCGHSA enrichment
  35. 2026-09-12 16:49 UTCEG score recompute
  36. 2026-09-12 16:49 UTCGHSA enrichment
  37. 2026-09-12 15:02 UTCEPSS rescore
  38. 2026-09-12 12:49 UTCGHSA enrichment
  39. 2026-09-12 08:48 UTCGHSA enrichment
  40. 2026-09-12 04:48 UTCGHSA enrichment
  41. 2026-09-12 00:48 UTCGHSA enrichment
  42. 2026-09-11 20:48 UTCGHSA enrichment
  43. 2026-09-11 16:43 UTCEG score recompute
  44. 2026-09-11 16:43 UTCGHSA enrichment
  45. 2026-09-11 14:53 UTCEPSS rescore
  46. 2026-09-11 14:53 UTCEPSS rescore
  47. 2026-09-11 12:43 UTCEG score recompute
  48. 2026-09-11 12:42 UTCGHSA enrichment
  49. 2026-09-11 08:41 UTCGHSA enrichment
  50. 2026-09-11 04:40 UTCGHSA enrichment
  51. 2026-09-11 00:40 UTCGHSA enrichment
  52. 2026-09-10 20:40 UTCGHSA enrichment
  53. 2026-09-10 16:40 UTCGHSA enrichment
  54. 2026-09-10 12:40 UTCGHSA enrichment
  55. 2026-09-10 08:39 UTCGHSA enrichment
  56. 2026-09-10 04:39 UTCGHSA enrichment
  57. 2026-09-10 00:34 UTCGHSA enrichment
  58. 2026-09-09 20:33 UTCEG score recompute
  59. 2026-09-09 20:32 UTCGHSA enrichment
  60. 2026-09-09 17:28 UTCEG score recompute
  61. 2026-09-09 16:55 UTCEG score recompute
  62. 2026-09-09 16:54 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-87929?
CVE-2026-87929 is a critical vulnerability published on September 9, 2026. MaxSite CMS through 109.6 ships with a hardcoded session encryption key in application/config/config.php that is never changed during installation, allowing unauthenticated attackers to forge administrator session cookies. Attackers can mint a malicious cisession cookie with administrator…
When was CVE-2026-87929 disclosed?
CVE-2026-87929 was first published in the National Vulnerability Database on September 9, 2026, with the most recent update on September 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-87929 actively exploited?
CVE-2026-87929 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 78.4% of all scored CVEs.
What is the CVSS score of CVE-2026-87929?
CVE-2026-87929 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-87929?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-87929, 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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