CVE-2026-107586

MEDIUMPre-NVD 4.34.3
EchelonGraph scoreHIGH confidence

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

Score 4.3 from GitHub Security Advisory published 2026-10-08. A secondary CVSS source baseline 4.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source

Also known asEUVD-2026-95038 (ENISA EUVD) · GHSA-q3hq-6rq3-6px5 (GitHub Security Advisories)Source: ENISA EUVD

4.3EG
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: 0.3%CVSS: 4.3Exploit: None knownExposed services: Not assessed

Upgrade to hMailServer 6.3.6, in which each account or administrator holds at most fifty sessions and gives up its own least recently used one, and a full table makes room out of the sessions of whoever holds the most (from the CVE record's solution, GitLab Inc.) — apply it.

Uncontrolled eviction in the browser session table of the REST API in Progressive Robot hMailServer 6.2.28 through 6.3.5 allows a remote authenticated user to end other users' sessions. The table of browser sessions, shared by every account, the server administrator and support sessions, dropped its least recently used session whenever it was full, whoever it belonged to, and placed no limit on how many sessions one account could hold. A user who repeatedly signs in with their own mailbox password can therefore keep the table full and sign out every webmail and administration session that is idle for more than a short time, for as long as they continue.

CVSS v3
4.3
EG Score
4.3MEDIUMhigh confidence
EG Risk
19
EG Risk 19/100

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)
Severity43% × 45%
Impact severity (EG Severity): CVSS 4.3 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.3% × 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 6.3.6, in which each account or administrator holds at most fifty sessions and gives up its own least recently used one, and a full table makes room out of the sessions of whoever holds the most (from the CVE record's solution, GitLab Inc.). Apply it within your standard update timelines.
EPSS PROB
0.3%
EPSS %ILE
27th
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 (4.3): severity, escalated by confirmed exploitation. This CVE's 4.3 is its impact severity (EG Severity), not escalated.

EG Severity
4.3 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.3% 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, and whom BOD 26-04 binds: 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 6.3.6, in which each account or administrator holds at most fifty sessions and gives up its own least recently used one, and a full table makes room out of the sessions of whoever holds the most (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.

The score's inputs: 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 8, 2026

Last Modified

October 8, 2026

Advisory Details (2)

Auto-updated Oct 8, 2026
Fix named in the CVE record's solution (GitLab Inc.).
Web page

REST API browser sessions: one account signing in over and over signed every other idle webmail and administration session out (#62) · Issues · hmailserver / hMailServer · GitLab

https://gitlab.com/hmailserver/hmailserver/-/work_items/62
Web page

hMailServer 6.3.6 · hmailserver / hMailServer · GitLab

https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6

Vendor Advisories for CVE-2026-107586(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 8× in last 7d / 46× 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 0.3% · 27th percentile
  2. 2026-10-31 16:31 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  3. 2026-10-31 11:25 UTCOSV refresh
  4. 2026-10-30 16:33 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  5. 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  6. 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  7. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  8. 2026-10-26 16:30 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  9. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  10. 2026-10-25 14:54 UTCEG score recompute
  11. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  12. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  13. 2026-10-23 08:41 UTCEG score recompute
  14. 2026-10-23 08:40 UTCGHSA enrichmentGHSA-q3hq-6rq3-6px5 · GitHub CVSS 4.3
  15. 2026-10-22 16:33 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  16. 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  17. 2026-10-20 16:32 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  18. 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  19. 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  20. 2026-10-18 05:07 UTCEG score recompute
  21. 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  22. 2026-10-16 16:40 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  23. 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  24. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  25. 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.3% · 25th percentile
Show 21 more
  1. 2026-10-12 16:38 UTCEG score recompute
  2. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  3. 2026-10-12 01:23 UTCGHSA enrichmentGHSA-q3hq-6rq3-6px5 · GitHub CVSS 4.3
  4. 2026-10-11 20:14 UTCEG score recompute
  5. 2026-10-11 18:26 UTCEG score recompute
  6. 2026-10-11 15:00 UTCEG score recompute
  7. 2026-10-11 13:47 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  8. 2026-10-11 00:00 UTCEG score recompute
  9. 2026-10-11 00:00 UTCGHSA enrichmentGHSA-q3hq-6rq3-6px5 · GitHub CVSS 4.3
  10. 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  11. 2026-10-09 22:39 UTCEG score recompute
  12. 2026-10-09 22:39 UTCGHSA enrichmentGHSA-q3hq-6rq3-6px5 · GitHub CVSS 4.3
  13. 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  14. 2026-10-08 21:17 UTCGHSA enrichmentGHSA-q3hq-6rq3-6px5 · GitHub CVSS 4.3
  15. 2026-10-08 20:20 UTCEG score recompute
  16. 2026-10-08 20:20 UTCGHSA enrichmentGHSA-q3hq-6rq3-6px5 · GitHub CVSS 4.3
  17. 2026-10-08 19:25 UTCEG score recompute
  18. 2026-10-08 19:25 UTCGHSA enrichmentGHSA-q3hq-6rq3-6px5 · GitHub CVSS 4.3
  19. 2026-10-08 15:20 UTCEG score recompute
  20. 2026-10-08 15:17 UTCEG score recomputeFirst assessed: 4.3 MEDIUM
  21. 2026-10-08 15:16 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-107586?
CVE-2026-107586 is a medium-severity vulnerability; its CVE record was published on October 8, 2026. Uncontrolled eviction in the browser session table of the REST API in Progressive Robot hMailServer 6.2.28 through 6.3.5 allows a remote authenticated user to end other users' sessions. The table of browser sessions, shared by every account, the server administrator and support sessions, dropped…
When was the CVE record for CVE-2026-107586 published?
The CVE record for CVE-2026-107586 was published on October 8, 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 8, 2026; the record at its source may have been updated since.
Is CVE-2026-107586 actively exploited?
CVE-2026-107586 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (27th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-107586?
CVE-2026-107586 has a CVSS base score of 4.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-107586?
The CVE record's solution for CVE-2026-107586, written by its CNA GitLab Inc., names the fix: "Upgrade to hMailServer 6.3.6, in which each account or administrator holds at most fifty sessions and gives up its own least recently used one, and a full table makes room out of the sessions of whoever holds the most." The vendor advisories EchelonGraph has for CVE-2026-107586 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-107586

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