CVE-2026-107569

HIGHPre-NVD 7.57.5
EchelonGraph scoreHIGH confidence

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

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-10-19. A secondary CVSS source baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Trending — 3 sources updated this week

Also known asEUVD-2026-104409 (ENISA EUVD) · GHSA-95hv-g278-w9p8 (GitHub Security Advisories)Source: ENISA EUVD

7.5EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 7.5Exploit: None knownExposed services: Not assessed

Upgrade to hMailServer 6.3.7, which reads X-hMailServer-LoopCount in one validated place (a count only when it is digits and never above the limit; anything else is read as the limit so no generated mail is made from it… (from the CVE record's solution, GitLab Inc.) — apply it.

Unchecked input for a loop condition in Progressive Robot hMailServer 6.0.0 through 6.3.6 allows a remote unauthenticated attacker to stop the server carrying mail. The server bounds the mail it generates in response to a message - a rule forward, reply or copy, an account forward, a Sieve redirect, vacation or notify, a bounce, an out-of-office reply - by a counter it carries in the message's X-hMailServer-LoopCount header, and makes no more once the counter reaches the configured rule loop limit (5 by default); that is what ends a forwarding or auto-reply cycle in a bounded number of hops. X-hMailServer-LoopCount is an ordinary header that is not stripped from mail arriving from outside, and the server read it with a signed conversion and no validation, so a count below zero passed every test against the limit: a sender who sets X-hMailServer-LoopCount to a negative value, or on the Linux builds to a value above the 32-bit signed range that the conversion wraps to a negative one, lifts the bound, and a message that enters a generated-mail cycle then loops up to about two thousand million times, each hop a queued message and a delivery, filling the queue and disk and stopping mail service. The Sieve notify action (from 6.2.22) consulted no limit at all, and its increment of the count could overflow a signed integer; and an account could reset the counter on its own mail through a Sieve editheader of the header (from 6.2.22) or a rule Set header value action (all versions) ahead of a forward or redirect.

CVSS v3
7.5
EG Score
7.5HIGHhigh confidence
EG Risk
49
EG Risk 49/100

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)
Severity75% × 45%
Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.4% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (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: Upgrade to hMailServer 6.3.7, which reads X-hMailServer-LoopCount in one validated place (a count only when it is digits and never above the limit; anything else is read as the limit so no generated mail is made from it… (from the CVE record's solution, GitLab Inc.). Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.4%
EPSS %ILE
31st
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 (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.

EG Severity
7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.4% 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; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days 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; Attend at high (mission-essential systems).

Upgrade to hMailServer 6.3.7, which reads X-hMailServer-LoopCount in one validated place (a count only when it is digits and never above the limit; anything else is read as the limit so no generated mail is made from it… (from the CVE record's solution, GitLab Inc.). Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (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)14 days if the affected system is publicly exposed; 60 days if it is not.

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

October 19, 2026

Last Modified

October 20, 2026

Advisory Details (2)

Auto-updated Oct 19, 2026
Fix named in the CVE record's solution (GitLab Inc.).
Web page

Sieve and rule loop guard: an outside sender's X-hMailServer-LoopCount, read unbounded, and a Sieve notify that consulted no limit, let the generated-mail loop bound be escaped (6.0.0-6.3.6) (#81) · Issues · hmailserver / hMailServer · GitLab

https://gitlab.com/hmailserver/hmailserver/-/work_items/81
Web page

hMailServer 6.3.7 · hmailserver / hMailServer · GitLab

https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.7

Vendor Advisories for CVE-2026-107569(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 9× in last 7d / 25× 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.

  1. 2026-11-01 16:33 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  2. 2026-10-31 16:31 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  3. 2026-10-30 16:33 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  4. 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  5. 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  6. 2026-10-28 15:48 UTCEG score recompute
  7. 2026-10-28 15:48 UTCGHSA enrichmentGHSA-95hv-g278-w9p8 · GitHub severity HIGH · GitHub CVSS 7.5
  8. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  9. 2026-10-26 16:30 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  10. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  11. 2026-10-25 14:54 UTCEG score recompute
  12. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  13. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  14. 2026-10-22 16:33 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  15. 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  16. 2026-10-20 20:26 UTCEG score recompute
  17. 2026-10-20 20:26 UTCGHSA enrichmentGHSA-95hv-g278-w9p8 · GitHub severity HIGH · GitHub CVSS 7.5
  18. 2026-10-20 19:38 UTCEG score recompute
  19. 2026-10-20 19:38 UTCGHSA enrichmentGHSA-95hv-g278-w9p8 · GitHub severity HIGH · GitHub CVSS 7.5
  20. 2026-10-20 16:32 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  21. 2026-10-19 21:36 UTCEG score recompute
  22. 2026-10-19 21:36 UTCGHSA enrichmentGHSA-95hv-g278-w9p8 · GitHub severity HIGH · GitHub CVSS 7.5
  23. 2026-10-19 16:31 UTCEG score recompute
  24. 2026-10-19 15:49 UTCEG score recomputeFirst assessed: 7.5 HIGH
  25. 2026-10-19 15:47 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-107569?
CVE-2026-107569 is a high-severity vulnerability; its CVE record was published on October 19, 2026. Unchecked input for a loop condition in Progressive Robot hMailServer 6.0.0 through 6.3.6 allows a remote unauthenticated attacker to stop the server carrying mail. The server bounds the mail it generates in response to a message - a rule forward, reply or copy, an account forward, a Sieve…
When was the CVE record for CVE-2026-107569 published?
The CVE record for CVE-2026-107569 was published on October 19, 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 20, 2026; the record at its source may have been updated since.
Is CVE-2026-107569 actively exploited?
CVE-2026-107569 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (31st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-107569?
CVE-2026-107569 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-107569?
The CVE record's solution for CVE-2026-107569, written by its CNA GitLab Inc., names the fix: "Upgrade to hMailServer 6.3.7, which reads X-hMailServer-LoopCount in one validated place (a count only when it is digits and never above the limit; anything else is read as the limit so no generated mail is made from it…" The vendor advisories EchelonGraph has for CVE-2026-107569 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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