CVE-2026-91122

HIGHPre-NVD 8.78.7
EchelonGraph scoreMEDIUM confidence

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

This high-severity CVE scores 8.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3% (17th 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-2026-86302 (ENISA EUVD)Source: ENISA EUVD

8.7EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 8.7Exploit: None knownExposed services: Not assessed

The CVE record names the fixed release — apply it.

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, the video placeholder component allowed crafted HTML to cause an attribute breakout and inject an attacker-controlled event handler. An authenticated user with default trust-level posting privileges could store the crafted placeholder in a post. When another user opened the post and clicked the video play overlay, the handler could execute arbitrary JavaScript in the viewer's session. Default Content Security Policy settings block inline event handlers, but instances with CSP disabled or relaxed could allow the script to read page content and make authenticated requests as the viewer. This issue is fixed in versions 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0.

CVSS v3
8.7
EG Score
8.7HIGHmedium confidence
EG Risk
39
EG Risk 39/100

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)
Severity87% × 45%
Impact severity (EG Severity): CVSS 8.7 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.3% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
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 none (CISA Vulnrichment) · Automatable no (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: The CVE record names the fixed release. Apply it within your standard update timelines.
EPSS PROB
0.3%
EPSS %ILE
17th
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 (8.7): severity, escalated by confirmed exploitation. This CVE's 8.7 is its impact severity (EG Severity), not escalated.

EG Severity
8.7 HIGHCVSS-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
0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-27). 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: 14 days if the affected system is publicly exposed; Fix on system upgrade 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; Track* at high (mission-essential systems).

The CVE record names the fixed release. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (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)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (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

September 24, 2026

Last Modified

September 24, 2026

Advisory Details (6)

Auto-updated Sep 24, 2026
Fix named in the CVE record. Sources: github, github_pr, github_commit.
GitHub commit

commit d7126af3264b (discourse/discourse)

Fix landed in discourse/discourse commit d7126af3264b — awaiting tagged release

https://github.com/discourse/discourse/commit/d7126af3264b672d2201d84c18a37cb8627424a8
GitHub commit

commit c3993e318e17 (discourse/discourse)

Fix landed in discourse/discourse commit c3993e318e17 — awaiting tagged release

https://github.com/discourse/discourse/commit/c3993e318e172389be5c98455177876f1dd87dda
GitHub commit

commit 5674b3e65948 (discourse/discourse)

Fix landed in discourse/discourse commit 5674b3e65948 — awaiting tagged release

https://github.com/discourse/discourse/commit/5674b3e6594825c28d2678e55057fd6802f11031
GitHub commit

commit 05d92b8749f6 (discourse/discourse)

Fix landed in discourse/discourse commit 05d92b8749f6 — awaiting tagged release

https://github.com/discourse/discourse/commit/05d92b8749f68d2626cbe65ec7adde7562a0283d
GitHub pull request

Security fixes for main

Fix merged in discourse/discourse PR #42882 on 2026-08-25 — awaiting tagged release

https://github.com/discourse/discourse/pull/42882
GitHub advisoryMentions a patch (unverified)

Stored XSS via video placeholder attribute breakout · Advisory · discourse/discourse · GitHub

https://github.com/discourse/discourse/security/advisories/GHSA-8m44-f6g9-7cg7

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 47× 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.

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. 1 repeat row among the latest 66 is merged into the row it repeats.

  1. 2026-11-02 16:46 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  2. 2026-11-01 16:36 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  3. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  4. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  5. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  6. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  7. 2026-10-27 19:43 UTCEG score recompute
  8. 2026-10-27 16:33 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  9. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  10. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  11. 2026-10-25 13:51 UTCEG score recompute
  12. 2026-10-24 16:34 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  13. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  14. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  15. 2026-10-21 16:34 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  16. 2026-10-20 16:34 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  17. 2026-10-20 07:02 UTCEG score recompute
  18. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  19. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  20. 2026-10-18 03:00 UTCEG score recompute
  21. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  22. 2026-10-16 16:45 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  23. 2026-10-15 16:33 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  24. 2026-10-14 16:34 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  25. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.3% · 16th percentile
Show 40 more
  1. 2026-10-13 04:42 UTCEG score recompute
  2. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  3. 2026-10-12 14:46 UTCEG score recompute
  4. 2026-10-11 19:13 UTCEG score recompute
  5. 2026-10-11 16:30 UTCEG score recompute
  6. 2026-10-11 13:50 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  7. 2026-10-11 13:44 UTCEG score recompute
  8. 2026-10-10 22:18 UTCEG score recompute
  9. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  10. 2026-10-09 21:53 UTCEG score recompute
  11. 2026-10-09 20:08 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  12. 2026-10-08 21:41 UTCEG score recompute
  13. 2026-10-08 17:14 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  14. 2026-10-08 09:15 UTCEG score recompute
  15. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  16. 2026-10-06 21:01 UTCEG score recompute
  17. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  18. 2026-10-05 20:52 UTCEG score recompute
  19. 2026-10-05 17:44 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  20. 2026-10-05 08:48 UTCEG score recompute
  21. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  22. 2026-10-03 20:35 UTCEG score recompute
  23. 2026-10-02 20:23 UTCEG score recompute
  24. 2026-10-01 20:13 UTCEG score recompute
  25. 2026-10-01 19:51 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  26. 2026-09-30 20:05 UTCEG score recompute
  27. 2026-09-30 15:04 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  28. 2026-09-29 19:55 UTCEG score recompute
  29. 2026-09-29 07:49 UTCEG score recompute
  30. 2026-09-28 19:45 UTCEG score recompute
  31. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  32. 2026-09-27 19:33 UTCEG score recompute
  33. 2026-09-27 13:49 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  34. 2026-09-26 19:23 UTCEG score recompute
  35. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  36. 2026-09-26 07:19 UTCEG score recompute
  37. 2026-09-24 18:35 UTCEG score recompute
  38. 2026-09-24 17:32 UTCEG score recompute
  39. 2026-09-24 17:02 UTCEG score recomputeFirst assessed: 8.7 HIGH
  40. 2026-09-24 17:01 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-91122?
CVE-2026-91122 is a high-severity vulnerability; its CVE record was published on September 24, 2026. Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, the video placeholder component allowed crafted HTML to cause an attribute breakout and inject an attacker-controlled event handler. An authenticated user with default trust-level posting…
When was the CVE record for CVE-2026-91122 published?
The CVE record for CVE-2026-91122 was published on September 24, 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 24, 2026; the record at its source may have been updated since.
Is CVE-2026-91122 actively exploited?
CVE-2026-91122 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (17th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-91122?
CVE-2026-91122 has a CVSS base score of 8.7 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-91122?
The CVE record for CVE-2026-91122 names the fix: "This issue is fixed in versions 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0."

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