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 8× in last 7d / 27× 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 210 total refreshes for this CVE.

  1. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-17 19:30 UTCEPSS rescore
  4. 2026-09-16 14:08 UTCEPSS rescore
  5. 2026-09-16 05:15 UTCEPSS rescore
  6. 2026-09-15 03:11 UTCEPSS rescore
  7. 2026-09-13 16:47 UTCEPSS rescore
  8. 2026-09-12 15:01 UTCEPSS rescore
  9. 2026-09-11 14:53 UTCEPSS rescore
  10. 2026-09-11 09:37 UTCEPSS rescore
  11. 2026-09-10 09:34 UTCEPSS rescore
  12. 2026-09-08 22:00 UTCEPSS rescore
  13. 2026-09-07 16:01 UTCEPSS rescore
  14. 2026-09-06 13:47 UTCEPSS rescore
  15. 2026-09-04 05:06 UTCEPSS rescore
  16. 2026-09-02 14:12 UTCEPSS rescore
  17. 2026-09-01 13:53 UTCEPSS rescore
  18. 2026-09-01 04:39 UTCEPSS rescore
  19. 2026-08-30 19:17 UTCEPSS rescore
  20. 2026-08-30 01:22 UTCEPSS rescore
  21. 2026-08-28 21:41 UTCEPSS rescore
  22. 2026-08-27 14:25 UTCEPSS rescore
  23. 2026-08-26 14:46 UTCEPSS rescore
  24. 2026-08-25 13:49 UTCEPSS rescore
  25. 2026-08-23 00:19 UTCEPSS rescore
Show 75 more
  1. 2026-08-21 23:49 UTCEPSS rescore
  2. 2026-08-20 22:55 UTCEPSS rescore
  3. 2026-08-19 17:03 UTCEPSS rescore
  4. 2026-08-18 13:48 UTCEPSS rescore
  5. 2026-08-17 13:48 UTCEG score recompute
  6. 2026-08-17 13:48 UTCVendor advisory
  7. 2026-08-17 13:48 UTCGHSA enrichment
  8. 2026-08-17 13:47 UTCEPSS rescore
  9. 2026-08-16 14:56 UTCEPSS rescore
  10. 2026-08-16 05:20 UTCEG score recompute
  11. 2026-08-16 05:20 UTCVendor advisory
  12. 2026-08-16 05:20 UTCGHSA enrichment
  13. 2026-08-16 02:14 UTCEPSS rescore
  14. 2026-08-15 01:31 UTCEG score recompute
  15. 2026-08-15 01:31 UTCVendor advisory
  16. 2026-08-15 01:31 UTCGHSA enrichment
  17. 2026-08-15 01:30 UTCEPSS rescore
  18. 2026-08-14 03:49 UTCEG score recompute
  19. 2026-08-14 03:49 UTCVendor advisory
  20. 2026-08-14 03:49 UTCGHSA enrichment
  21. 2026-08-13 22:00 UTCEPSS rescore
  22. 2026-08-12 21:25 UTCEG score recompute
  23. 2026-08-12 21:25 UTCVendor advisory
  24. 2026-08-12 21:25 UTCGHSA enrichment
  25. 2026-08-12 13:51 UTCEPSS rescore
  26. 2026-08-11 23:33 UTCEG score recompute
  27. 2026-08-11 23:33 UTCVendor advisory
  28. 2026-08-11 23:33 UTCGHSA enrichment
  29. 2026-08-11 13:43 UTCEPSS rescore
  30. 2026-08-11 01:50 UTCEG score recompute
  31. 2026-08-11 01:50 UTCVendor advisory
  32. 2026-08-11 01:50 UTCGHSA enrichment
  33. 2026-08-11 00:00 UTCEPSS rescore
  34. 2026-08-10 00:43 UTCEG score recompute
  35. 2026-08-10 00:43 UTCVendor advisory
  36. 2026-08-10 00:43 UTCGHSA enrichment
  37. 2026-08-09 13:46 UTCEPSS rescore
  38. 2026-08-09 03:00 UTCEG score recompute
  39. 2026-08-09 03:00 UTCVendor advisory
  40. 2026-08-09 03:00 UTCGHSA enrichment
  41. 2026-08-08 16:37 UTCEPSS rescore
  42. 2026-08-07 18:03 UTCEG score recompute
  43. 2026-08-07 18:03 UTCVendor advisory
  44. 2026-08-07 18:03 UTCGHSA enrichment
  45. 2026-08-06 20:20 UTCEG score recompute
  46. 2026-08-06 20:20 UTCVendor advisory
  47. 2026-08-06 20:20 UTCGHSA enrichment
  48. 2026-08-06 13:46 UTCEPSS rescore
  49. 2026-08-05 22:37 UTCEG score recompute
  50. 2026-08-05 22:37 UTCVendor advisory
  51. 2026-08-05 22:37 UTCGHSA enrichment
  52. 2026-08-05 19:17 UTCEPSS rescore
  53. 2026-08-04 15:10 UTCEPSS rescore
  54. 2026-08-04 10:38 UTCEPSS rescore
  55. 2026-08-03 20:27 UTCEG score recompute
  56. 2026-08-03 20:27 UTCVendor advisory
  57. 2026-08-03 20:27 UTCGHSA enrichment
  58. 2026-08-03 10:36 UTCEPSS rescore
  59. 2026-08-02 05:42 UTCEG score recompute
  60. 2026-08-02 05:42 UTCVendor advisory
  61. 2026-08-02 05:42 UTCGHSA enrichment
  62. 2026-08-02 02:27 UTCEPSS rescore
  63. 2026-08-01 04:16 UTCEPSS rescore
  64. 2026-07-30 16:28 UTCEPSS rescore
  65. 2026-07-30 01:30 UTCEPSS rescore
  66. 2026-07-28 15:36 UTCEPSS rescore
  67. 2026-07-27 14:13 UTCEPSS rescore
  68. 2026-07-26 14:54 UTCEPSS rescore
  69. 2026-07-26 14:54 UTCEPSS rescore
  70. 2026-07-25 14:18 UTCEPSS rescore
  71. 2026-07-24 14:17 UTCEPSS rescore
  72. 2026-07-23 03:11 UTCEG score recompute
  73. 2026-07-22 14:08 UTCEPSS rescore
  74. 2026-07-21 15:24 UTCEPSS rescore
  75. 2026-07-20 17:08 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 68.9% 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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