CVE-2026-45117

CRITICALPre-NVD 9.89.8
EchelonGraph scoreMEDIUM confidence

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

This critical-severity CVE scores 9.8 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 1.1% (66th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source

Also known asEUVD-2026-61020 (ENISA EUVD)Source: ENISA EUVD

9.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1.1%CVSS: 9.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

MyBB is free and open source forum software. From 1.8.13 until 1.8.40, the installer module does not properly escape user-supplied database configuration values written to the configuration file, resulting in PHP code injection and remote code execution when the installer is available. install/index.php processes the values with addcslashes(), but the $characters argument added in MyBB 1.8.13 does not include the backslash character, allowing crafted input to escape the generated PHP string. The uniquely identifying implementation details include introduced in MyBB 1.8.13. This issue is fixed in version 1.8.40.

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
60
EG Risk 60/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity98% × 45%
Impact severity (EG Severity): CVSS 9.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation1.1% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (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 at low or medium mission impact and sooner than that at high.
EPSS PROB
1.1%
EPSS %ILE
66th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.

EG Severity
9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
EG Likelihood
1.1% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-01). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 3 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track 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 total (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)3 days if the affected system is publicly exposed; 60 days if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (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

August 18, 2026

Last Modified

September 8, 2026

Advisory Details (4)

Auto-updated Oct 31, 2026
Patch available. Sources: github_commit, github_release, github.
Web page

Version 1.8.40 - MyBB

https://mybb.com/versions/1.8.40
GitHub advisoryMentions a patch (unverified)

Installer database configuration RCE · Advisory · mybb/mybb · GitHub

https://github.com/mybb/mybb/security/advisories/GHSA-gpc4-77rp-3xqr
GitHub release Patch Available

mybb_1840

Patch available: mybb/mybb mybb_1840

https://github.com/mybb/mybb/releases/tag/mybb_1840
GitHub commit Patch Available

commit 0fe713e3b964 (mybb/mybb)

Patch available: mybb/mybb mybb_1840 (contains commit 0fe713e3b964)

https://github.com/mybb/mybb/commit/0fe713e3b964bfc878ea65bdd9f746f585f6ebbf

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 14× in last 7d / 60× 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 140 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 40 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-02 09:02 UTCEG score recompute
  2. 2026-11-01 16:34 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  3. 2026-11-01 10:44 UTCEG score recompute
  4. 2026-10-31 16:32 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  5. 2026-10-31 12:25 UTCEG score recompute
  6. 2026-10-30 16:34 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  7. 2026-10-30 14:08 UTCEG score recompute
  8. 2026-10-29 16:33 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  9. 2026-10-28 17:31 UTCEG score recompute
  10. 2026-10-28 16:32 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  11. 2026-10-27 19:10 UTCEG score recompute
  12. 2026-10-27 16:32 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  13. 2026-10-26 20:49 UTCEG score recompute
  14. 2026-10-26 16:31 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  15. 2026-10-25 20:32 UTCEG score recompute
  16. 2026-10-25 16:33 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  17. 2026-10-25 14:27 UTCEG score recompute
  18. 2026-10-24 22:14 UTCEG score recompute
  19. 2026-10-24 16:33 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  20. 2026-10-23 23:53 UTCEG score recompute
  21. 2026-10-23 16:31 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  22. 2026-10-23 01:31 UTCEG score recompute
  23. 2026-10-22 16:34 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  24. 2026-10-22 02:51 UTCEG score recompute
  25. 2026-10-21 16:33 UTCEPSS rescoreEPSS 1.1% · 66th percentile
Show 75 more
  1. 2026-10-21 04:31 UTCEG score recompute
  2. 2026-10-20 16:33 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  3. 2026-10-20 06:12 UTCEG score recompute
  4. 2026-10-19 16:32 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  5. 2026-10-19 07:53 UTCEG score recompute
  6. 2026-10-18 16:32 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  7. 2026-10-18 03:38 UTCEG score recompute
  8. 2026-10-17 16:34 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  9. 2026-10-17 11:12 UTCEG score recompute
  10. 2026-10-16 16:42 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  11. 2026-10-16 12:52 UTCEG score recompute
  12. 2026-10-15 16:32 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  13. 2026-10-15 14:33 UTCEG score recompute
  14. 2026-10-14 16:33 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  15. 2026-10-14 09:09 UTCEG score recompute
  16. 2026-10-13 16:34 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  17. 2026-10-13 06:08 UTCEG score recompute
  18. 2026-10-12 16:34 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  19. 2026-10-12 16:04 UTCEG score recompute
  20. 2026-10-11 19:46 UTCEG score recompute
  21. 2026-10-11 17:01 UTCEG score recompute
  22. 2026-10-11 14:26 UTCEG score recompute
  23. 2026-10-11 13:48 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  24. 2026-10-10 20:00 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  25. 2026-10-09 20:07 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  26. 2026-10-08 17:12 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  27. 2026-10-07 23:48 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  28. 2026-10-06 17:07 UTCEG score recompute
  29. 2026-10-06 15:18 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  30. 2026-10-06 08:23 UTCEG score recompute
  31. 2026-10-05 17:43 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  32. 2026-10-05 01:56 UTCEG score recompute
  33. 2026-10-04 23:22 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  34. 2026-10-03 17:39 UTCEG score recompute
  35. 2026-10-03 14:25 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  36. 2026-10-02 19:18 UTCEG score recompute
  37. 2026-10-02 01:28 UTCEG score recompute
  38. 2026-10-01 19:50 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  39. 2026-09-30 20:50 UTCEG score recompute
  40. 2026-09-30 15:03 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  41. 2026-09-30 09:48 UTCEG score recompute
  42. 2026-09-28 21:56 UTCEG score recompute
  43. 2026-09-27 16:27 UTCEG score recompute
  44. 2026-09-27 13:48 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  45. 2026-09-27 07:56 UTCEG score recompute
  46. 2026-09-26 15:58 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  47. 2026-09-24 17:06 UTCEG score recompute
  48. 2026-09-23 20:49 UTCEG score recompute
  49. 2026-09-23 17:53 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  50. 2026-09-22 20:26 UTCEG score recompute
  51. 2026-09-21 23:53 UTCEG score recompute
  52. 2026-09-20 22:37 UTCEG score recompute
  53. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  54. 2026-09-19 19:29 UTCEG score recompute
  55. 2026-09-18 22:49 UTCEG score recompute
  56. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  57. 2026-09-17 21:51 UTCEG score recompute
  58. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  59. 2026-09-16 15:09 UTCEG score recompute
  60. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  61. 2026-09-16 05:31 UTCEG score recompute
  62. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  63. 2026-09-15 04:11 UTCEG score recompute
  64. 2026-09-13 18:30 UTCEG score recompute
  65. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  66. 2026-09-12 18:08 UTCEG score recompute
  67. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  68. 2026-09-11 17:49 UTCEG score recompute
  69. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  70. 2026-09-11 09:41 UTCEG score recompute
  71. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  72. 2026-09-10 13:17 UTCEG score recompute
  73. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  74. 2026-09-09 03:26 UTCEG score recompute
  75. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.8% · 54th percentile

Frequently asked(5)

What is CVE-2026-45117?
CVE-2026-45117 is a critical-severity vulnerability; its CVE record was published on August 18, 2026. MyBB is free and open source forum software. From 1.8.13 until 1.8.40, the installer module does not properly escape user-supplied database configuration values written to the configuration file, resulting in PHP code injection and remote code execution when the installer is available.…
When was the CVE record for CVE-2026-45117 published?
The CVE record for CVE-2026-45117 was published on August 18, 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 September 8, 2026; the record at its source may have been updated since.
Is CVE-2026-45117 actively exploited?
CVE-2026-45117 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.1% probability of exploitation in the next 30 days (66th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-45117?
CVE-2026-45117 has a CVSS base score of 9.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-45117?
A fix for CVE-2026-45117 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-45117

Explore →

Is Your Infrastructure Affected by CVE-2026-45117?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.