The Linux live-update apply helper (hmailserver-update) of Progressive Robot hMailServer 6.3.4 and 6.3.5 runs as root on a request file written by the unprivileged hmailserver service account, and took from that request the program used to verify an AppImage update's signature and the systemd unit to stop before reading the service account's files. An attacker who already runs code as the hmailserver service account, for example through another flaw in the mail server, can therefore have arbitrary code executed as root, on any Linux installation where the live update's path unit is active - the default for the project's .deb and .rpm packages - and on AppImage installations run under that unit.
CVE-2026-104658
HIGHPre-NVD 7.87.8—Trending — 4 sources updated this week
EchelonGraph scoreHIGH confidence
Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-10-08. A secondary CVSS source baseline 7.8; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
7.8EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.1%CVSS: 7.8Exploit: None knownExposed services: Not assessed
No fix is confirmed yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for the fix.
- CVSS v3
- 7.8
- EG Score
- 7.8HIGHhigh confidence
- EG Risk
- 35EG Risk 35/100CISA 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 computedSeverity78% × 45%Exploitation0% × 40%Automatability0% × 15%CISA SSVC: Track at low or medium mission impact; Track* at high (mission-essential systems).Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix. - EPSS PROB
- 0.1%
- EPSS %ILE
- 1st
- KEV
- Not listed
CISA SSVCTrack at low or medium mission impact; Track* at high (mission-essential systems).
No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.
Exploitation none (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 8, 2026
Last Modified
October 8, 2026
Advisory Details (2)
Auto-updated Oct 8, 2026No fix on record yet.
generic
hMailServer 6.3.6 · hmailserver / hMailServer · GitLab
https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6generic
Linux live update: the root apply helper took its verifier and the unit it stops from the service account's request (#58) · Issues · hmailserver / hMailServer · GitLab
https://gitlab.com/hmailserver/hmailserver/-/work_items/58Vendor Advisories for CVE-2026-104658(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 13× in last 7d / 13× 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.
- 2026-10-10 07:44 UTCGHSA enrichment
- 2026-10-09 20:16 UTCEG score recompute
- 2026-10-09 20:16 UTCGHSA enrichment
- 2026-10-09 20:06 UTCEPSS rescore
- 2026-10-09 08:47 UTCGHSA enrichment
- 2026-10-08 21:19 UTCGHSA enrichment
- 2026-10-08 18:38 UTCEG score recompute
- 2026-10-08 18:38 UTCGHSA enrichment
- 2026-10-08 17:51 UTCEG score recompute
- 2026-10-08 17:50 UTCGHSA enrichment
- 2026-10-08 11:24 UTCEG score recompute
- 2026-10-08 10:57 UTCEG score recompute
- 2026-10-08 10:56 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-104658?
CVE-2026-104658 is a high vulnerability published on October 8, 2026. The Linux live-update apply helper (hmailserver-update) of Progressive Robot hMailServer 6.3.4 and 6.3.5 runs as root on a request file written by the unprivileged hmailserver service account, and took from that request the program used to verify an AppImage update's signature and the systemd unit…
When was CVE-2026-104658 disclosed?
CVE-2026-104658 was first published on October 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-104658 actively exploited?
CVE-2026-104658 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.1% probability of exploitation in the next 30 days (1st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-104658?
CVE-2026-104658 has a CVSS base score of 7.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-104658?
No fix for CVE-2026-104658 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The vendor advisories EchelonGraph has for CVE-2026-104658 are linked in the Vendor Advisories panel on this page.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-104658
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