CVE-2026-107568

MEDIUMPre-NVD 6.56.5
EchelonGraph scoreHIGH confidence

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

Score 6.5 from GitHub Security Advisory published 2026-10-19. A secondary CVSS source baseline 6.5; 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-2026-104407 (ENISA EUVD) · GHSA-625v-xcvx-8hhv (GitHub Security Advisories)Source: ENISA EUVD

6.5EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 6.5Exploit: None knownExposed services: Not assessed

Upgrade to hMailServer 6.3.7, which uses a Sieve notify :from only when it is an address that reaches the account (the account's own address or an active alias of it) - otherwise the notification goes from the account's… (from the CVE record's solution, GitLab Inc.) — apply it.

Missing authorization in the Sieve notify action (6.2.22 through 6.3.6) and in the mail-rule Reply action (6.0.0 through 6.3.6) of Progressive Robot hMailServer allows an authenticated user to send mail through the server as any address. A Sieve notify sends a notification message, and its :from tag names the sender; the server set the notification's From header to that :from as the script wrote it, without checking that the address belongs to the account - the check that the Sieve vacation action applies to its own :from, and that the server applies to the sender of mail queued over COM or sent from the webmail. An account that can store a Sieve script (over ManageSieve, the REST API's self-service filter, or the administration interface) could therefore have the server send a notification from any address, on this server or anywhere; and where the claimed address is at a domain the server hosts with DKIM signing enabled, the server signed the notification with that domain's DKIM key, because it signs by the From header's domain, producing forged mail aligned to pass the domain's DMARC policy. The notify action and this behaviour were introduced in 6.2.22. In the mail-rule engine, a rule's Reply was likewise sent from whatever address the action named, whoever the rule belonged to, so that an account acting on its own rules over COM, a domain administrator, or an API key confined to a domain (over the REST API from 6.3.4) could have a domain's or an account's rule reply from any address, signed, where that address is at a domain the server hosts with DKIM signing enabled, with that domain's key.

CVSS v3
6.5
EG Score
6.5MEDIUMhigh confidence
EG Risk
29
EG Risk 29/100

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)
Severity65% × 45%
Impact severity (EG Severity): CVSS 6.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.2% × 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 every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (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 uses a Sieve notify :from only when it is an address that reaches the account (the account's own address or an active alias of it) - otherwise the notification goes from the account's… (from the CVE record's solution, GitLab Inc.). Apply it within your standard update timelines.
EPSS PROB
0.2%
EPSS %ILE
15th
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 (6.5): severity, escalated by confirmed exploitation. This CVE's 6.5 is its impact severity (EG Severity), not escalated.

EG Severity
6.5 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-24). 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 every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

Upgrade to hMailServer 6.3.7, which uses a Sieve notify :from only when it is an address that reaches the account (the account's own address or an active alias of it) - otherwise the notification goes from the account's… (from the CVE record's solution, GitLab Inc.). Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (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)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (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 notify and mail-rule Reply: a script's :from, or a rule's reply address, was used as the sender without checking it belongs to the account or the rule's owner, so mail could be sent as any address, DKIM-signed by the server (6.0.0-6.3.6) (#82) · Issues · hmailserver / hMailServer · GitLab

https://gitlab.com/hmailserver/hmailserver/-/work_items/82
Web page

hMailServer 6.3.7 · hmailserver / hMailServer · GitLab

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

Vendor Advisories for CVE-2026-107568(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 / 21× 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. 2026-10-30 16:33 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  2. 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  3. 2026-10-28 17:55 UTCOSV refresh
  4. 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  5. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  6. 2026-10-26 16:30 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  7. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  8. 2026-10-25 14:54 UTCEG score recompute
  9. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  10. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  11. 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  12. 2026-10-20 20:26 UTCEG score recompute
  13. 2026-10-20 20:26 UTCGHSA enrichmentGHSA-625v-xcvx-8hhv · GitHub CVSS 6.5
  14. 2026-10-20 19:38 UTCEG score recompute
  15. 2026-10-20 19:38 UTCGHSA enrichmentGHSA-625v-xcvx-8hhv · GitHub CVSS 6.5
  16. 2026-10-20 16:32 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  17. 2026-10-19 21:50 UTCEG score recompute
  18. 2026-10-19 21:50 UTCGHSA enrichmentGHSA-625v-xcvx-8hhv · GitHub CVSS 6.5
  19. 2026-10-19 16:37 UTCEG score recompute
  20. 2026-10-19 15:49 UTCEG score recomputeFirst assessed: 6.5 MEDIUM
  21. 2026-10-19 15:47 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-107568?
CVE-2026-107568 is a medium-severity vulnerability; its CVE record was published on October 19, 2026. Missing authorization in the Sieve notify action (6.2.22 through 6.3.6) and in the mail-rule Reply action (6.0.0 through 6.3.6) of Progressive Robot hMailServer allows an authenticated user to send mail through the server as any address. A Sieve notify sends a notification message, and its :from…
When was the CVE record for CVE-2026-107568 published?
The CVE record for CVE-2026-107568 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-2026-107568 actively exploited?
CVE-2026-107568 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (15th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-107568?
CVE-2026-107568 has a CVSS base score of 6.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-107568?
The CVE record's solution for CVE-2026-107568, written by its CNA GitLab Inc., names the fix: "Upgrade to hMailServer 6.3.7, which uses a Sieve notify :from only when it is an address that reaches the account (the account's own address or an active alias of it) - otherwise the notification goes from the account's…" The vendor advisories EchelonGraph has for CVE-2026-107568 are linked in the Vendor Advisories panel on this page.

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