CVE-2026-40687

MEDIUMNVD 4.84.8—
EchelonGraph scoreMEDIUM confidence

Score 4.8 from GitHub Security Advisory published 2026-05-01. NVD baseline CVSS 4.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
4.8EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.8Exploit: None knownExposed: 0

A fix is available — apply it.

In Exim before 4.99.2, when the SPA authentication driver is used with an adversarial SPA resource, there can be an out-of-bounds write that crashes the connection instance, or erroneous data processing that divulges data from uninitialized heap memory.

CVSS v3
4.8
EG Score
4.8(medium)
EG Risk
22(Track)
EG Risk 22/100SSVC: Track

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
Severity48% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
31%
KEV
Not listed

Published

April 30, 2026

Last Modified

May 1, 2026

Advisory Details (3)

Auto-updated May 1, 2026
No patch confirmed yet.
generic

oss-security - Exim 4.99.2 fixes 4 CVEs

https://www.openwall.com/lists/oss-security/2026/04/30/21
generic
https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40687.assessment
generic

SPA authenticator: harden buffer usage · 68b963b9f7 - exim/exim - Exim Forgejo

https://code.exim.org/exim/exim/commit/68b963b9f75ca27b38e1c0f8c87037990199f505

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntueximon4 (4.99.1-1ubuntu1.1) @ resolute2026-06-14ubuntu
ubuntueximon4 (4.86.2-2ubuntu2.6+esm9) @ xenial2026-06-14ubuntu

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

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
exim44.100~RC1-1 ... 4.99~RC3-2 (121 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
exim44.96-15 ... 4.96-15+deb12u8 (9 versions)4.96-15+deb12u9—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
exim44.98.2-1, 4.98.2-1+deb13u14.98.2-1+deb13u2—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
exim44.98.2-1 ... 4.99~RC3-2 (25 versions)4.99.2-1—

Weakness Classification(1)

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

All Vendor Advisories

(2)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 7× in last 7d / 29× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

Showing the most recent 100 of 205 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-40687?
CVE-2026-40687 is a medium vulnerability published on April 30, 2026. In Exim before 4.99.2, when the SPA authentication driver is used with an adversarial SPA resource, there can be an out-of-bounds write that crashes the connection instance, or erroneous data processing that divulges data from uninitialized heap memory.
When was CVE-2026-40687 disclosed?
CVE-2026-40687 was first published in the National Vulnerability Database on April 30, 2026, with the most recent update on May 1, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-40687 actively exploited?
CVE-2026-40687 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 69.3% of all scored CVEs.
What is the CVSS score of CVE-2026-40687?
CVE-2026-40687 has a CVSS v3 base score of 4.8 (NVD).
How do I remediate CVE-2026-40687?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-40687, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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