CVE-2026-105798

HIGHPre-NVD 8.78.7
EchelonGraph scoreLOW confidence

This high-severity CVE scores 8.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: secondary
Elevated
8.7EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: —CVSS: 8.7Exploit: Elevated riskExposed services: Not assessed

The CVE record names the fixed release — apply it.

SimpleChat is a secure AI conversation application with personal and group workspaces for document-grounded interactions. Prior to 0.261.029, POST /api/group_documents/upload stores an attacker-controlled group document filename that group_workspaces.html later interpolates into inline Share event handlers. The escapeGroupHtml function leaves apostrophes unchanged, while escapeHtml produces an HTML entity that the browser decodes before JavaScript evaluation, so either path permits the filename to terminate the handler string. An authenticated group Owner, Admin, or DocumentManager can persist script that executes in the SimpleChat origin when another group member clicks Share, allowing access to victim-visible data and actions with the victim session. This issue is fixed in version 0.261.029.

CVSS v3
8.7
EG Score
8.7HIGHlow confidence
EG Risk
55
EG Risk 55/100CISA 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
Severity87% × 45%
Exploitation40% × 40%
Automatability0% × 15%
CISA SSVC: Track at low, Track* at medium and Attend at high mission impact.
Action: The CVE record names the fixed release. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
—
EPSS %ILE
—
KEV
Not listed

CISA SSVCTrack at low, Track* at medium and Attend at high mission impact.

The CVE record names the fixed release. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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

October 6, 2026

Last Modified

October 6, 2026

Advisory Details (2)

Auto-updated Oct 6, 2026
🔬 Proof of concept available. Fix named in the CVE record. Sources: github, github_commit.
github_commit

commit 537a259eb048 (microsoft/simplechat)

Fix landed in microsoft/simplechat commit 537a259eb048 — awaiting tagged release

https://github.com/microsoft/simplechat/commit/537a259eb048b8f6d1c94193fa0c9683ab0bace9
githubMentions a patch (unverified)🟡 PoC Available

Stored XSS via group document filename in inline onclick handler · Advisory · microsoft/simplechat · GitHub

https://github.com/microsoft/simplechat/security/advisories/GHSA-qwcw-r653-j8c6

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 4× in last 7d / 4× 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. 2026-10-06 15:31 UTCEG score recompute
  2. 2026-10-06 14:55 UTCEG score recompute
  3. 2026-10-06 14:30 UTCEG score recompute
  4. 2026-10-06 14:29 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(4)

What is CVE-2026-105798?
CVE-2026-105798 is a high vulnerability published on October 6, 2026. SimpleChat is a secure AI conversation application with personal and group workspaces for document-grounded interactions. Prior to 0.261.029, POST /api/groupdocuments/upload stores an attacker-controlled group document filename that groupworkspaces.html later interpolates into inline Share event…
When was CVE-2026-105798 disclosed?
CVE-2026-105798 was first published on October 6, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-105798?
CVE-2026-105798 has a CVSS base score of 8.7 (a secondary CVSS source that NVD displays; NVD's own analysis pending). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-105798?
The CVE record for CVE-2026-105798 names the fix: "This issue is fixed in version 0.261.029."

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-105798

Explore →

Is Your Infrastructure Affected by CVE-2026-105798?

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

Book a Demo →Browse All CVEs