CVE-2026-40017

MEDIUMPre-NVD 6.56.5
EchelonGraph scoreMEDIUM confidence

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

Score 6.5 from GitHub Security Advisory published 2026-08-28. 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
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: 0.3%CVSS: 6.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

An attacker that can send mail to a user can craft a message header whose values are chosen to collide in an internal hash table, which makes the IMAP THREAD command consume CPU disproportionate to the size of the message. This is a separate issue from CVE-2026-40014 and is not addressed by that fix. Whenever a mail client issues a THREAD command on the affected mailbox, this can cause degradation or denial of service for IMAP. Monitor system for abnormal CPU usage, kill the offending process and remove the offending message from the affected mailbox. Update to non-vulnerable version. No publicly available exploits are known.

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

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 computed (value × EchelonGraph’s weight)
Severity65% × 45%
The EG Score, 6.5 of 10.
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: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.3%
EPSS %ILE
24th
KEV
Not listed

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

A fix is available. 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

August 28, 2026

Last Modified

September 3, 2026

Advisory Details (1)

Auto-updated Aug 28, 2026
Patch available.
Web page
https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0003.json

Vendor Advisories for CVE-2026-40017(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

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 ... 1:2.4.5+dfsg1-3 (43 versions)
  • every version on: no fix on record
—
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 17× in last 7d / 73× 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.

Showing the most recent 99 of 118 refreshes 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. 1 repeat row among the latest 100 is merged into the row it repeats. The 19 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  2. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  3. 2026-10-12 16:09 UTCEG score recompute
  4. 2026-10-11 19:52 UTCEG score recompute
  5. 2026-10-11 17:05 UTCEG score recompute
  6. 2026-10-11 14:32 UTCEG score recompute
  7. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  8. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  9. 2026-10-10 05:18 UTCEG score recompute
  10. 2026-10-10 05:18 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  11. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  12. 2026-10-09 03:01 UTCEG score recompute
  13. 2026-10-09 03:01 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  14. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  15. 2026-10-08 00:55 UTCEG score recompute
  16. 2026-10-08 00:54 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  17. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  18. 2026-10-06 20:40 UTCEG score recompute
  19. 2026-10-06 20:40 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  20. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  21. 2026-10-05 18:30 UTCEG score recompute
  22. 2026-10-05 18:30 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  23. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  24. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  25. 2026-10-04 16:25 UTCEG score recompute
Show 74 more
  1. 2026-10-04 16:25 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  2. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  3. 2026-10-03 14:20 UTCEG score recompute
  4. 2026-10-03 14:20 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  5. 2026-10-02 08:03 UTCEG score recompute
  6. 2026-10-02 08:03 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  7. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  8. 2026-10-01 05:58 UTCEG score recompute
  9. 2026-10-01 05:58 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  10. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  11. 2026-09-30 03:52 UTCEG score recompute
  12. 2026-09-30 03:52 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  13. 2026-09-28 21:09 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  14. 2026-09-27 17:42 UTCEG score recompute
  15. 2026-09-27 17:42 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  16. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  17. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  18. 2026-09-26 15:37 UTCEG score recompute
  19. 2026-09-26 15:37 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  20. 2026-09-26 00:26 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  21. 2026-09-25 12:26 UTCEG score recompute
  22. 2026-09-25 12:26 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  23. 2026-09-24 10:21 UTCEG score recompute
  24. 2026-09-24 10:21 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  25. 2026-09-23 08:15 UTCEG score recompute
  26. 2026-09-23 08:15 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  27. 2026-09-22 06:10 UTCEG score recompute
  28. 2026-09-22 06:10 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  29. 2026-09-21 04:04 UTCEG score recompute
  30. 2026-09-21 04:04 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  31. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  32. 2026-09-20 01:59 UTCEG score recompute
  33. 2026-09-20 01:59 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  34. 2026-09-18 23:53 UTCEG score recompute
  35. 2026-09-18 23:53 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  36. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  37. 2026-09-17 21:48 UTCEG score recompute
  38. 2026-09-17 21:48 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  39. 2026-09-17 19:30 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  40. 2026-09-16 19:41 UTCEG score recompute
  41. 2026-09-16 19:41 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  42. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  43. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  44. 2026-09-15 17:35 UTCEG score recompute
  45. 2026-09-15 17:35 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  46. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  47. 2026-09-14 15:26 UTCEG score recompute
  48. 2026-09-14 15:26 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  49. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  50. 2026-09-13 13:20 UTCEG score recompute
  51. 2026-09-13 13:20 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  52. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  53. 2026-09-12 11:14 UTCEG score recompute
  54. 2026-09-12 11:14 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  55. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  56. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  57. 2026-09-11 09:08 UTCEG score recompute
  58. 2026-09-11 09:08 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  59. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  60. 2026-09-10 07:02 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  61. 2026-09-09 04:56 UTCEG score recompute
  62. 2026-09-09 04:56 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  63. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  64. 2026-09-08 02:51 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  65. 2026-09-07 00:44 UTCEG score recompute
  66. 2026-09-07 00:44 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  67. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  68. 2026-09-05 22:38 UTCEG score recompute
  69. 2026-09-05 22:38 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  70. 2026-09-04 20:33 UTCEG score recompute
  71. 2026-09-04 20:32 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  72. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  73. 2026-09-03 18:22 UTCGHSA enrichmentGHSA-gr5f-599w-cg8j · GitHub CVSS 6.5
  74. 2026-09-03 03:07 UTCEG score recompute

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-40017?
CVE-2026-40017 is a medium-severity vulnerability; its CVE record was published on August 28, 2026. An attacker that can send mail to a user can craft a message header whose values are chosen to collide in an internal hash table, which makes the IMAP THREAD command consume CPU disproportionate to the size of the message. This is a separate issue from CVE-2026-40014 and is not addressed by that…
When was the CVE record for CVE-2026-40017 published?
The CVE record for CVE-2026-40017 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-2026-40017 actively exploited?
CVE-2026-40017 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (24th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-40017?
CVE-2026-40017 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-2026-40017?
A fix for CVE-2026-40017 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-40017 are linked in the Vendor Advisories panel on this page.

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