CVE-2026-40685

MEDIUMNVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

Score 6.5 from GitHub Security Advisory published 2026-05-01. NVD baseline CVSS 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
6.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 6.5Exploit: NoneExposed: 0

A fix is available — apply it.

In Exim before 4.99.2, when JSON lookup is enabled, an out-of-bounds heap write can occur when a JSON operator encounters malformed JSON in an untrusted header, because of an incorrect implementation of \ skipping.

CVSS v3
6.5
EG Score
6.5(medium)
EG Risk
—
EPSS
24.4%
KEV
Not listed

Published

April 30, 2026

Last Modified

May 1, 2026

Advisory Details (3)

Auto-updated Apr 30, 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/CVE2026-40685.assessment
generic

when dewrap, only skip \ if associated char · 9fdc057e71 - exim/exim - Exim Forgejo

https://code.exim.org/exim/exim/commit/9fdc057e71b87c87a0d3d2288b2810a0efaaba57

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntueximon4 (4.99.1-1ubuntu1.1) @ resolute2026-06-14ubuntu
ubuntueximon4 (4.90.1-1ubuntu1.10+esm6) @ bionic2026-06-14ubuntu

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.

Weakness Classification(2)

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 / 34× 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 113 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-40685?
CVE-2026-40685 is a medium vulnerability published on April 30, 2026. In Exim before 4.99.2, when JSON lookup is enabled, an out-of-bounds heap write can occur when a JSON operator encounters malformed JSON in an untrusted header, because of an incorrect implementation of \ skipping.
When was CVE-2026-40685 disclosed?
CVE-2026-40685 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-2026-40685 actively exploited?
CVE-2026-40685 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 24.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-40685?
CVE-2026-40685 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-40685?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-40685, 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.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-40685

Explore →

Is Your Infrastructure Affected by CVE-2026-40685?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs