CVE-2026-43876

MEDIUMNVD 6.46.4
EchelonGraph scoreMEDIUM confidence

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

Score 6.4 from GitHub Security Advisory published 2026-05-05. NVD baseline CVSS 6.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 3 sources updated this weekElevated

Also known asEUVD-2026-29312 (ENISA EUVD) · GHSA-g9cm-rxp7-6gv5 (GitHub Security Advisories)Source: ENISA EUVD

6.4EG
EchelonGraph verdictPlan mitigationRemediate within your standard update timelines (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 6.4Exploit: No code on recordExposed services: Not assessed

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

The CVE record's description, written by its CNA (GitHub, Inc.), states the affected versions: "In versions up to and including 29.0, objects/notifySubscribers.json.php takes the raw message POST parameter and passes it into sendSiteEmail(), which substitutes it directly into an HTML email template (via str_replac…" No release containing a fix is confirmed on record.

WWBN AVideo is an open source video platform. In versions up to and including 29.0, objects/notifySubscribers.json.php takes the raw message POST parameter and passes it into sendSiteEmail(), which substitutes it directly into an HTML email template (via str_replace on the {message} placeholder) and renders it with PHPMailer::msgHTML(). There is no HTML sanitization, character escaping, or output encoding on the attacker-controlled message between $_POST['message'] and the rendered email. Any authenticated user with upload permission can therefore broadcast arbitrary HTML — phishing links, tracking pixels, CSS/UI spoofing — to every subscriber on their channel (up to 10,000 recipients per invocation). The email is sent From: the platform's configured contact address and wrapped in the site's official logo and title, so attacker-supplied HTML arrives with the appearance of an official platform communication. Commit https://github.com/WWBN/AVideo/commit/ contains an updated fix.

CVSS v3
6.4
EG Score
6.4MEDIUMmedium confidence
EG Risk
45
EG Risk 45/100

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)
Severity64% × 45%
Impact severity (EG Severity): CVSS 6.4 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (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: No fix is confirmed yet. Restrict network exposure of the affected system within your standard update timelines, and watch for a fix.
EPSS PROB
0.2%
EPSS %ILE
8th
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 (6.4): severity, escalated by confirmed exploitation. This CVE's 6.4 is its impact severity (EG Severity), not escalated.

EG Severity
6.4 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS. 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; Track* at high (mission-essential systems).CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

No fix is confirmed yet. Restrict network exposure of the affected system within your standard update timelines, and watch for a fix.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (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)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (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

May 11, 2026

Last Modified

October 26, 2026

Advisory Details (2)

Auto-updated May 11, 2026
No fix on record yet. Sources: github.
GitHub advisoryMentions a patch (unverified)

HTML Injection in notifySubscribers.json.php Enables Platform-Branded Phishing Emails to Channel Subscribers · Advisory · WWBN/AVideo · GitHub

https://github.com/WWBN/AVideo/security/advisories/GHSA-g9cm-rxp7-6gv5
Web page

feat: Ensure message is sanitized and converted to plain text before … · WWBN/AVideo@078c434 · GitHub

https://github.com/WWBN/AVideo/commit/078c4342eb9969a70425a9cdca3eefa7f8a86d53

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
composerwwbn/avideo—ghsa

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
Packagist(1)
PackageVulnerable rangeFix by version rangeDependents
wwbn/avideo10.4 ... 29.0 (18 versions)
  • every version through 29.0: no fix on record
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 39× 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 227 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 127 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  2. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  3. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  4. 2026-10-26 18:49 UTCEG score recompute
  5. 2026-10-26 18:48 UTCGHSA enrichmentGHSA-g9cm-rxp7-6gv5 · GitHub CVSS 6.4
  6. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  7. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  8. 2026-10-25 14:28 UTCEG score recompute
  9. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  10. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  11. 2026-10-23 01:36 UTCEG score recompute
  12. 2026-10-23 01:36 UTCGHSA enrichmentGHSA-g9cm-rxp7-6gv5 · GitHub CVSS 6.4
  13. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  14. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  15. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  16. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  17. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  18. 2026-10-18 03:39 UTCEG score recompute
  19. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  20. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  21. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  22. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  23. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  24. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  25. 2026-10-12 16:05 UTCEG score recompute
Show 75 more
  1. 2026-10-11 19:47 UTCEG score recompute
  2. 2026-10-11 17:02 UTCEG score recompute
  3. 2026-10-11 14:28 UTCEG score recompute
  4. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  5. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  6. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  7. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  8. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  9. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  10. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  11. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  12. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  13. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  14. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  15. 2026-09-30 06:58 UTCOSV refresh
  16. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  17. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  18. 2026-09-23 17:53 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  19. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  20. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  21. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  22. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  23. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  24. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  25. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  26. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  27. 2026-09-11 11:53 UTCOSV refresh
  28. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  29. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  30. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  31. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  32. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  33. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  34. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  35. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  36. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  37. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  38. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  39. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  40. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  41. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  42. 2026-08-23 18:33 UTCEG score recompute
  43. 2026-08-23 18:33 UTCGHSA enrichmentGHSA-g9cm-rxp7-6gv5 · GitHub CVSS 6.4
  44. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  45. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  46. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  47. 2026-08-19 17:04 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  48. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  49. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  50. 2026-08-17 11:00 UTCEG score recompute
  51. 2026-08-17 11:00 UTCGHSA enrichmentGHSA-g9cm-rxp7-6gv5 · GitHub CVSS 6.4
  52. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  53. 2026-08-16 04:21 UTCEG score recompute
  54. 2026-08-16 04:21 UTCGHSA enrichmentGHSA-g9cm-rxp7-6gv5 · GitHub CVSS 6.4
  55. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  56. 2026-08-15 01:37 UTCEG score recompute
  57. 2026-08-15 01:37 UTCGHSA enrichmentGHSA-g9cm-rxp7-6gv5 · GitHub CVSS 6.4
  58. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  59. 2026-08-14 02:53 UTCEG score recompute
  60. 2026-08-14 02:53 UTCGHSA enrichmentGHSA-g9cm-rxp7-6gv5 · GitHub CVSS 6.4
  61. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  62. 2026-08-12 22:37 UTCEG score recompute
  63. 2026-08-12 22:37 UTCGHSA enrichmentGHSA-g9cm-rxp7-6gv5 · GitHub CVSS 6.4
  64. 2026-08-12 13:51 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  65. 2026-08-11 23:52 UTCEG score recompute
  66. 2026-08-11 23:52 UTCGHSA enrichmentGHSA-g9cm-rxp7-6gv5 · GitHub CVSS 6.4
  67. 2026-08-11 13:43 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  68. 2026-08-11 01:08 UTCEG score recompute
  69. 2026-08-11 01:07 UTCGHSA enrichmentGHSA-g9cm-rxp7-6gv5 · GitHub CVSS 6.4
  70. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  71. 2026-08-10 00:55 UTCEG score recompute
  72. 2026-08-10 00:55 UTCGHSA enrichmentGHSA-g9cm-rxp7-6gv5 · GitHub CVSS 6.4
  73. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  74. 2026-08-09 02:11 UTCEG score recompute
  75. 2026-08-09 02:11 UTCGHSA enrichmentGHSA-g9cm-rxp7-6gv5 · GitHub CVSS 6.4

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Frequently asked(5)

What is CVE-2026-43876?
CVE-2026-43876 is a medium-severity vulnerability; its CVE record was published on May 11, 2026. WWBN AVideo is an open source video platform. In versions up to and including 29.0, objects/notifySubscribers.json.php takes the raw message POST parameter and passes it into sendSiteEmail(), which substitutes it directly into an HTML email template (via strreplace on the {message} placeholder) and…
When was the CVE record for CVE-2026-43876 published?
The CVE record for CVE-2026-43876 was published on May 11, 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 October 26, 2026; the record at its source may have been updated since.
Is CVE-2026-43876 actively exploited?
CVE-2026-43876 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (8th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-43876?
CVE-2026-43876 has a CVSS v3 base score of 6.4 (NVD).
How do I remediate CVE-2026-43876?
No fix for CVE-2026-43876 is confirmed yet. Until one is published, restrict network exposure of the affected system — for example, keep it off the internet or limit it to trusted networks — and watch for a fix. The CVE record's description, written by its CNA (GitHub, Inc.), states the affected versions: "In versions up to and including 29.0, objects/notifySubscribers.json.php takes the raw message POST parameter and passes it into sendSiteEmail(), which substitutes it directly into an HTML email template (via str_replac…" No release containing a fix is confirmed on record.

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