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
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: None knownExposed: 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
29(Track)
EG Risk 29/100SSVC: 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
Severity65% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
25%
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.

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(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 / 28× 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 199 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. 2026-09-06 13:47 UTCEPSS rescore
  9. 2026-09-04 05:06 UTCEPSS rescore
  10. 2026-09-02 14:12 UTCEPSS rescore
  11. 2026-09-01 13:53 UTCEPSS rescore
  12. 2026-09-01 04:39 UTCEPSS rescore
  13. 2026-08-30 19:17 UTCEPSS rescore
  14. 2026-08-30 01:22 UTCEPSS rescore
  15. 2026-08-28 21:41 UTCEPSS rescore
  16. 2026-08-27 14:25 UTCEPSS rescore
  17. 2026-08-26 14:46 UTCEPSS rescore
  18. 2026-08-25 13:49 UTCEPSS rescore
  19. 2026-08-23 00:19 UTCEPSS rescore
  20. 2026-08-21 23:49 UTCEPSS rescore
  21. 2026-08-20 22:55 UTCEPSS rescore
  22. 2026-08-19 17:03 UTCEPSS rescore
  23. 2026-08-18 13:48 UTCEPSS rescore
  24. 2026-08-17 13:48 UTCEG score recompute
  25. 2026-08-17 13:48 UTCVendor advisory
Show 75 more
  1. 2026-08-17 13:48 UTCGHSA enrichment
  2. 2026-08-17 13:47 UTCEPSS rescore
  3. 2026-08-16 14:56 UTCEPSS rescore
  4. 2026-08-16 05:20 UTCEG score recompute
  5. 2026-08-16 05:20 UTCVendor advisory
  6. 2026-08-16 05:20 UTCGHSA enrichment
  7. 2026-08-16 02:14 UTCEPSS rescore
  8. 2026-08-15 01:30 UTCEPSS rescore
  9. 2026-08-14 03:49 UTCEG score recompute
  10. 2026-08-14 03:49 UTCVendor advisory
  11. 2026-08-14 03:49 UTCGHSA enrichment
  12. 2026-08-13 22:00 UTCEPSS rescore
  13. 2026-08-12 17:27 UTCEG score recompute
  14. 2026-08-12 17:27 UTCVendor advisory
  15. 2026-08-12 17:27 UTCGHSA enrichment
  16. 2026-08-12 13:51 UTCEPSS rescore
  17. 2026-08-11 13:43 UTCEPSS rescore
  18. 2026-08-11 08:01 UTCEG score recompute
  19. 2026-08-11 08:01 UTCVendor advisory
  20. 2026-08-11 08:01 UTCGHSA enrichment
  21. 2026-08-11 00:00 UTCEPSS rescore
  22. 2026-08-10 06:40 UTCEG score recompute
  23. 2026-08-10 06:40 UTCVendor advisory
  24. 2026-08-10 06:40 UTCGHSA enrichment
  25. 2026-08-09 13:46 UTCEPSS rescore
  26. 2026-08-09 05:20 UTCEG score recompute
  27. 2026-08-09 05:20 UTCVendor advisory
  28. 2026-08-09 05:20 UTCGHSA enrichment
  29. 2026-08-08 16:37 UTCEPSS rescore
  30. 2026-08-08 04:00 UTCEG score recompute
  31. 2026-08-08 04:00 UTCVendor advisory
  32. 2026-08-08 04:00 UTCGHSA enrichment
  33. 2026-08-07 02:39 UTCEG score recompute
  34. 2026-08-07 02:39 UTCVendor advisory
  35. 2026-08-07 02:39 UTCGHSA enrichment
  36. 2026-08-06 13:46 UTCEPSS rescore
  37. 2026-08-05 22:37 UTCEG score recompute
  38. 2026-08-05 22:37 UTCVendor advisory
  39. 2026-08-05 22:37 UTCGHSA enrichment
  40. 2026-08-05 19:17 UTCEPSS rescore
  41. 2026-08-04 15:10 UTCEPSS rescore
  42. 2026-08-04 10:38 UTCEPSS rescore
  43. 2026-08-03 20:27 UTCEG score recompute
  44. 2026-08-03 20:27 UTCVendor advisory
  45. 2026-08-03 20:27 UTCGHSA enrichment
  46. 2026-08-03 10:36 UTCEPSS rescore
  47. 2026-08-02 05:42 UTCEG score recompute
  48. 2026-08-02 05:42 UTCVendor advisory
  49. 2026-08-02 05:42 UTCGHSA enrichment
  50. 2026-08-01 04:16 UTCEPSS rescore
  51. 2026-07-30 16:28 UTCEPSS rescore
  52. 2026-07-30 01:30 UTCEPSS rescore
  53. 2026-07-28 15:36 UTCEPSS rescore
  54. 2026-07-27 14:13 UTCEPSS rescore
  55. 2026-07-26 14:54 UTCEPSS rescore
  56. 2026-07-26 14:54 UTCEPSS rescore
  57. 2026-07-25 14:18 UTCEPSS rescore
  58. 2026-07-24 14:17 UTCEPSS rescore
  59. 2026-07-23 14:18 UTCEPSS rescore
  60. 2026-07-23 14:18 UTCEPSS rescore
  61. 2026-07-23 03:11 UTCEG score recompute
  62. 2026-07-22 14:08 UTCEPSS rescore
  63. 2026-07-21 15:24 UTCEPSS rescore
  64. 2026-07-20 17:08 UTCEPSS rescore
  65. 2026-07-19 14:31 UTCEPSS rescore
  66. 2026-07-19 02:29 UTCEPSS rescore
  67. 2026-07-18 10:04 UTCEPSS rescore
  68. 2026-07-16 17:03 UTCEPSS rescore
  69. 2026-07-15 16:57 UTCEPSS rescore
  70. 2026-07-15 16:57 UTCEPSS rescore
  71. 2026-07-15 02:00 UTCEPSS rescore
  72. 2026-07-13 22:30 UTCEPSS rescore
  73. 2026-07-13 06:13 UTCEPSS rescore
  74. 2026-07-13 06:13 UTCEPSS rescore
  75. 2026-07-12 05:46 UTCEPSS rescore

Related CVEs(same vendor + same CWE)

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 0% probability of exploitation in the next 30 days, which ranks it in the top 75.1% of all scored CVEs.
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.

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