Inefficient algorithmic complexity in the JSON reader of Progressive Robot hMailServer allows a remote unauthenticated attacker to make the mail services unavailable. Reading a JSON object kept the first of each duplicated member name by searching the members already read, so an object of N distinct member names cost O(N^2): 1 MB took 8.9 seconds and 4 MB took 300 seconds against the affected code. A remote attacker reaches the reader without an account by mailing a crafted TLS-RPT report (up to 16 MB after decompression) to a hosted domain's published report mailbox, which is read on a delivery thread; a few such reports hold every delivery thread (ten by default), so the server delivers no mail, local or outbound, for over an hour per report. A signed-in account reaches the same 16 MB body through the webmail's own REST routes, holding the REST API's own worker threads. Where no report mailbox is configured, the unauthenticated REST sign-in routes that read a JSON body are capped at 64 KB and are not affected.
CVE-2026-107574
Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-10-08. A secondary CVSS source baseline 7.5; sources differ by 0.0.
- High severity, but no confirmed exploitation yet
No fix is confirmed yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for the fix.
- CVSS v3
- 7.5
- EG Score
- 7.5HIGHhigh confidence
- EG Risk
- 49EG Risk 49/100CISA 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 computedSeverity75% × 45%Exploitation0% × 40%Automatability100% × 15%CISA SSVC: Track at low or medium mission impact; Attend 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 at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix. - EPSS PROB
- 0.4%
- EPSS %ILE
- 35th
- KEV
- Not listed
CISA SSVCTrack at low or medium mission impact; Attend 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 at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (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, 2026hMailServer 6.3.6 · hmailserver / hMailServer · GitLab
https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6The JSON reader kept the first of each duplicated member name in time quadratic in the object; a 16 MB TLS-RPT report mailed to a domain's report mailbox reached it without an account (6.3.2-6.3.5) (#76) · Issues · hmailserver / hMailServer · GitLab
https://gitlab.com/hmailserver/hmailserver/-/work_items/76Vendor Advisories for CVE-2026-107574(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 12× in last 7d / 12× 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.
- 2026-10-09 22:22 UTCEG score recompute
- 2026-10-09 22:22 UTCGHSA enrichment
- 2026-10-09 20:06 UTCEPSS rescore
- 2026-10-09 09:51 UTCGHSA enrichment
- 2026-10-08 21:18 UTCGHSA enrichment
- 2026-10-08 15:23 UTCEG score recompute
- 2026-10-08 15:23 UTCGHSA enrichment
- 2026-10-08 14:52 UTCEG score recompute
- 2026-10-08 14:52 UTCGHSA enrichment
- 2026-10-08 12:26 UTCEG score recompute
- 2026-10-08 11:52 UTCEG score recompute
- 2026-10-08 11:51 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-107574?
When was CVE-2026-107574 disclosed?
Is CVE-2026-107574 actively exploited?
What is the CVSS score of CVE-2026-107574?
How do I remediate CVE-2026-107574?
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-107574
Is Your Infrastructure Affected by CVE-2026-107574?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.