CVE-2017-16943

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-13. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Elevated
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 47%CVSS: 9.8Exploit: NoneExposed: 0

A fix is available — apply it.

The receive_msg function in receive.c in the SMTP daemon in Exim 4.88 and 4.89 allows remote attackers to execute arbitrary code or cause a denial of service (use-after-free) via vectors involving BDAT commands.

CVSS v3
9.8
EG Score
9.8(medium)
EPSS
98.7%
KEV
Not listed

Published

November 25, 2017

Last Modified

May 13, 2026

Advisory Details (10)

Auto-updated Jun 22, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic

[exim-announce] Critical Exim Security Vulnerability: disable chunking

https://lists.exim.org/lurker/message/20171125.034842.d1d75cac.en.html
generic

PoC-Exploit-Mirror/CVE-2017-16944 at master · LetUsFsck/PoC-Exploit-Mirror · GitHub

https://github.com/LetUsFsck/PoC-Exploit-Mirror/tree/master/CVE-2017-16944
generic

exim - Exim Forgejo

https://git.exim.org/exim.git/commitdiff/4e6ae6235c68de243b1c2419027472d7659aa2b4
generic

exim - Exim Forgejo

https://git.exim.org/exim.git/commit/4090d62a4b25782129cc1643596dc2f6e8f63bde
generic

Exim Internet Mailer

https://bugs.exim.org/show_bug.cgi?id=2199
generic
http://www.securitytracker.com/id/1039872
generic🟡 PoC Available

oss-security - 21Nails: Multiple vulnerabilities in Exim

http://www.openwall.com/lists/oss-security/2021/05/04/7
generic🟡 PoC Available

oss-security - Re: RCE in Exim reported

http://openwall.com/lists/oss-security/2017/11/25/3
generic🟡 PoC Available

oss-security - RCE in Exim reported

http://openwall.com/lists/oss-security/2017/11/25/2
generic

oss-security - Re: RCE in Exim reported

http://openwall.com/lists/oss-security/2017/11/25/1

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuexim4-daemon-light (4.88-5ubuntu1.2) @ zesty2026-05-20ubuntu

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.

All Vendor Advisories

(1)

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 3× in last 7d / 23× 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.

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

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Frequently asked(5)

What is CVE-2017-16943?
CVE-2017-16943 is a critical vulnerability published on November 25, 2017. The receive_msg function in receive.c in the SMTP daemon in Exim 4.88 and 4.89 allows remote attackers to execute arbitrary code or cause a denial of service (use-after-free) via vectors involving BDAT commands.
When was CVE-2017-16943 disclosed?
CVE-2017-16943 was first published in the National Vulnerability Database on November 25, 2017, with the most recent update on May 13, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2017-16943 actively exploited?
CVE-2017-16943 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 98.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2017-16943?
CVE-2017-16943 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2017-16943?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2017-16943, 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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