CVE-2026-42391

HIGHPre-NVD 7.57.5
EchelonGraph scoreMEDIUM confidence

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

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-08-28. 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

Also known asEUVD-2026-67674 (ENISA EUVD) · GHSA-7597-pg24-8mv9 (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

A fix is available — apply it.

An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before logging in, which causes memory and CPU usage to grow disproportionately. The login process can be terminated by the out-of-memory handling, which also terminates all other connections handled by the same process. This can cause degradation or denial of service for IMAP logins. Limit the number of connections handled by a single imap-login process. This has a performance impact though. Update to non-vulnerable version. No publicly available exploits are known.

CVSS v3
7.5
EG Score
7.5HIGHmedium 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: A fix is available. 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
39th
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 2026-11-06). 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).

A fix is available. 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

August 28, 2026

Last Modified

September 3, 2026

Advisory Details (1)

Auto-updated Aug 28, 2026
Patch available.

Patch Availability(3)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatdovecot-1:2.3.16-18.el9_8.82026-10-12redhat
redhatdovecot-1:2.3.21-19.el10_2.82026-10-08redhat
redhatdovecot-1:2.3.16-16.el8_102026-10-06redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(5 across 5 ecosystems)
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
dovecot—
  • every version up to 2.4.5-r0: fixed in 2.4.5-r0
—
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
dovecot—
  • every version up to 2.4.5-r0: fixed in 2.4.5-r0
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
dovecot1:2.3.19.1+dfsg1-2.1 ... 1:2.3.19.1+dfsg1-2.1+deb12u6 (7 versions)
  • every version up to 1:2.3.19.1+dfsg1-2.1+deb12u7: fixed in 1:2.3.19.1+dfsg1-2.1+deb12u7
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
dovecot1:2.4.1+dfsg1-6 ... 1:2.4.1+dfsg1-6+deb13u6 (7 versions)
  • every version up to 1:2.4.1+dfsg1-6+deb13u7: fixed in 1:2.4.1+dfsg1-6+deb13u7
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
dovecot1:2.4.1+dfsg1-6 ... 1:2.4.4+dfsg1-2 (12 versions)
  • every version up to 1:2.4.5+dfsg1-1: fixed in 1:2.4.5+dfsg1-1
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 9× in last 7d / 38× 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 its CVE.org record (CNA or CISA ADP). 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). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

Showing the most recent 100 of 210 rows on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 110 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-12 16:33 UTCEPSS rescoreEPSS 0.4% · 39th percentile
  2. 2026-11-11 16:39 UTCEPSS rescoreEPSS 0.4% · 39th percentile
  3. 2026-11-10 16:44 UTCEPSS rescoreEPSS 0.4% · 39th percentile
  4. 2026-11-09 16:35 UTCEPSS rescoreEPSS 0.4% · 39th percentile
  5. 2026-11-08 16:39 UTCEPSS rescoreEPSS 0.4% · 39th percentile
  6. 2026-11-07 16:39 UTCEPSS rescoreEPSS 0.4% · 39th percentile
  7. 2026-11-06 22:02 UTCEchelonGraph re-scored
  8. 2026-11-06 22:02 UTCVendor advisory
  9. 2026-11-06 22:02 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  10. 2026-11-06 16:37 UTCEPSS rescoreEPSS 0.4% · 39th percentile
  11. 2026-11-05 16:37 UTCEPSS rescoreEPSS 0.4% · 39th percentile
  12. 2026-11-04 16:35 UTCEPSS rescoreEPSS 0.4% · 39th percentile
  13. 2026-11-03 16:48 UTCEPSS rescoreEPSS 0.4% · 39th percentile
  14. 2026-11-02 16:44 UTCEPSS rescoreEPSS 0.4% · 39th percentile
  15. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.4% · 39th percentile
  16. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.4% · 39th percentile
  17. 2026-10-31 03:30 UTCEchelonGraph re-scored
  18. 2026-10-31 03:30 UTCVendor advisory
  19. 2026-10-31 03:30 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  20. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.4% · 39th percentile
  21. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  22. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  23. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  24. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  25. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.4% · 38th percentile
Show 75 more
  1. 2026-10-25 14:29 UTCEchelonGraph re-scored
  2. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  3. 2026-10-24 08:58 UTCEchelonGraph re-scored
  4. 2026-10-24 08:58 UTCVendor advisory
  5. 2026-10-24 08:58 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  6. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  7. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  8. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  9. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  10. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  11. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  12. 2026-10-18 03:41 UTCEchelonGraph re-scored
  13. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  14. 2026-10-17 14:26 UTCEchelonGraph re-scored
  15. 2026-10-17 14:26 UTCVendor advisory
  16. 2026-10-17 14:26 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  17. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  18. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  19. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  20. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  21. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  22. 2026-10-12 16:07 UTCEchelonGraph re-scored
  23. 2026-10-11 19:49 UTCEchelonGraph re-scored
  24. 2026-10-11 17:03 UTCEchelonGraph re-scored
  25. 2026-10-11 14:29 UTCEchelonGraph re-scored
  26. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  27. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  28. 2026-10-10 13:51 UTCVendor advisory
  29. 2026-10-10 13:51 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  30. 2026-10-10 00:59 UTCEchelonGraph re-scored
  31. 2026-10-10 00:59 UTCVendor advisory
  32. 2026-10-10 00:58 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  33. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  34. 2026-10-09 02:42 UTCEchelonGraph re-scored
  35. 2026-10-09 02:42 UTCVendor advisory
  36. 2026-10-09 02:42 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  37. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  38. 2026-10-08 00:54 UTCEchelonGraph re-scored
  39. 2026-10-08 00:54 UTCVendor advisory
  40. 2026-10-08 00:54 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  41. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  42. 2026-10-07 09:25 UTCVendor advisory
  43. 2026-10-07 09:25 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  44. 2026-10-06 20:28 UTCEchelonGraph re-scored
  45. 2026-10-06 20:28 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  46. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  47. 2026-10-06 07:28 UTCEchelonGraph re-scored
  48. 2026-10-06 07:28 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  49. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  50. 2026-10-05 17:42 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  51. 2026-10-05 04:52 UTCEchelonGraph re-scored
  52. 2026-10-05 04:52 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  53. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  54. 2026-10-04 16:00 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  55. 2026-10-04 03:09 UTCEchelonGraph re-scored
  56. 2026-10-04 03:09 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  57. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  58. 2026-10-03 14:19 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  59. 2026-10-03 00:28 UTCEchelonGraph re-scored
  60. 2026-10-03 00:28 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  61. 2026-10-02 10:21 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  62. 2026-10-01 21:31 UTCEchelonGraph re-scored
  63. 2026-10-01 21:31 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  64. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  65. 2026-10-01 08:40 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  66. 2026-09-30 19:50 UTCEchelonGraph re-scored
  67. 2026-09-30 19:50 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  68. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  69. 2026-09-30 03:52 UTCEchelonGraph re-scored
  70. 2026-09-30 03:52 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  71. 2026-09-29 14:21 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  72. 2026-09-29 01:27 UTCEchelonGraph re-scored
  73. 2026-09-29 01:27 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  74. 2026-09-28 12:37 UTCGHSA enrichmentGHSA-7597-pg24-8mv9 · GitHub severity HIGH · GitHub CVSS 7.5
  75. 2026-09-27 23:47 UTCEchelonGraph re-scored

Frequently asked(5)

What is CVE-2026-42391?
CVE-2026-42391 is a high-severity vulnerability; its CVE record was published on August 28, 2026. An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before logging in, which causes memory and CPU usage to grow disproportionately. The login process can be terminated by the out-of-memory handling, which also terminates all other connections handled by…
When was the CVE record for CVE-2026-42391 published?
The CVE record for CVE-2026-42391 was published on August 28, 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 September 3, 2026; the record at its source may have been updated since.
Is CVE-2026-42391 actively exploited?
CVE-2026-42391 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (39th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-42391?
CVE-2026-42391 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-2026-42391?
A fix for CVE-2026-42391 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-42391 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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