CRITICAL
exim: use-after-free in receive_msg function via vectors involving BDAT commands
Published Nov 25, 2017
9.8
CRITICALCVSS 3.0
EPSS 46.71%
Description
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.
Affected products
Remediation
Red Hat mitigation
if you are running Exim 4.88 or newer, then in the main section of your Exim configuration, set: chunking_advertise_hosts = This disables advertising the ESMTP CHUNKING extension, making the BDAT verb unavailable and avoids letting an attacker apply the logic.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
9.8 CRITICAL NVD
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality Impact High
Integrity Impact High
Availability Impact High
7.5 HIGH NVD
AV:N/AC:L/Au:N/C:P/I:P/A:P
Access Vector Network
Access Complexity Low
Authentication None
Confidentiality Impact Partial
Integrity Impact Partial
Availability Impact Partial
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
46.71% 0.46705
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
EPSS probability 0.46705
Score over time
2021–2026- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (62 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 46.71% (0.46705) | 98.79th | v5 (v2026.06.15) |
| Sep 22, 2026 | 46.71% (0.46705) | 98.77th | v5 (v2026.06.15) |
| Sep 21, 2026 | 43.65% (0.43646) | 98.72th | v5 (v2026.06.15) |
| Sep 6, 2026 | 46.71% (0.46705) | 98.74th | v5 (v2026.06.15) |
| Sep 5, 2026 | 43.65% (0.43646) | 98.69th | v5 (v2026.06.15) |
| Aug 30, 2026 | 46.71% (0.46705) | 98.74th | v5 (v2026.06.15) |
| Aug 28, 2026 | 43.65% (0.43646) | 98.69th | v5 (v2026.06.15) |
| Aug 24, 2026 | 46.71% (0.46705) | 98.73th | v5 (v2026.06.15) |
| Aug 23, 2026 | 43.65% (0.43646) | 98.68th | v5 (v2026.06.15) |
| Jun 15, 2026 | 46.71% (0.46705) | 98.67th | v5 (v2026.06.15) |
| May 26, 2026 | 74.53% (0.74526) | 98.87th | v4 (v2025.03.14) |
| Apr 9, 2026 | 76.92% (0.76925) | 98.96th | v4 (v2025.03.14) |
| Mar 4, 2026 | 74.50% (0.74500) | 98.82th | v4 (v2025.03.14) |
| Mar 1, 2026 | 70.17% (0.70165) | 98.66th | v4 (v2025.03.14) |
| Feb 4, 2026 | 74.50% (0.74500) | 98.81th | v4 (v2025.03.14) |
| Feb 1, 2026 | 69.74% (0.69740) | 98.63th | v4 (v2025.03.14) |
| Jan 4, 2026 | 74.50% (0.74500) | 98.80th | v4 (v2025.03.14) |
| Jan 1, 2026 | 69.74% (0.69740) | 98.61th | v4 (v2025.03.14) |
| Dec 28, 2025 | 76.66% (0.76664) | 98.90th | v4 (v2025.03.14) |
| Dec 27, 2025 | 79.65% (0.79647) | 99.05th | v4 (v2025.03.14) |
| Dec 4, 2025 | 76.66% (0.76664) | 98.89th | v4 (v2025.03.14) |
| Dec 1, 2025 | 72.71% (0.72707) | 98.72th | v4 (v2025.03.14) |
| Nov 18, 2025 | 76.99% (0.76989) | 99.04th | v4 (v2025.03.14) |
| Nov 4, 2025 | 75.77% (0.75765) | 98.85th | v4 (v2025.03.14) |
| Nov 1, 2025 | 71.24% (0.71243) | 98.66th | v4 (v2025.03.14) |
| Oct 28, 2025 | 75.77% (0.75765) | 98.85th | v4 (v2025.03.14) |
| Oct 27, 2025 | 78.88% (0.78882) | 99.01th | v4 (v2025.03.14) |
| Oct 4, 2025 | 75.77% (0.75765) | 98.86th | v4 (v2025.03.14) |
| Oct 1, 2025 | 71.24% (0.71243) | 98.67th | v4 (v2025.03.14) |
| Sep 4, 2025 | 78.88% (0.78882) | 99.02th | v4 (v2025.03.14) |
| Sep 1, 2025 | 70.95% (0.70955) | 98.65th | v4 (v2025.03.14) |
| Aug 17, 2025 | 78.88% (0.78882) | 99.01th | v4 (v2025.03.14) |
| Aug 4, 2025 | 77.19% (0.77188) | 98.92th | v4 (v2025.03.14) |
| Aug 1, 2025 | 70.95% (0.70955) | 98.65th | v4 (v2025.03.14) |
| Jul 30, 2025 | 77.19% (0.77188) | 98.92th | v4 (v2025.03.14) |
| Jul 4, 2025 | 75.77% (0.75765) | 98.84th | v4 (v2025.03.14) |
| Jul 1, 2025 | 71.24% (0.71243) | 98.64th | v4 (v2025.03.14) |
| Jun 4, 2025 | 76.41% (0.76408) | 98.86th | v4 (v2025.03.14) |
| Jun 1, 2025 | 72.01% (0.72010) | 98.66th | v4 (v2025.03.14) |
| May 4, 2025 | 76.41% (0.76408) | 98.86th | v4 (v2025.03.14) |
| May 1, 2025 | 72.01% (0.72010) | 98.66th | v4 (v2025.03.14) |
| Mar 30, 2025 | 76.41% (0.76408) | 98.88th | v4 (v2025.03.14) |
| Mar 29, 2025 | 79.66% (0.79665) | 98.83th | v4 (v2025.03.14) |
| Mar 28, 2025 | 76.41% (0.76408) | 98.87th | v4 (v2025.03.14) |
| Mar 17, 2025 | 79.31% (0.79307) | 99.02th | v4 (v2025.03.14) |
| Dec 17, 2024 | 12.83% (0.12827) | 95.47th | v3 (v2023.03.01) |
| Aug 12, 2024 | 52.70% (0.52704) | 97.64th | v3 (v2023.03.01) |
| Aug 10, 2024 | 21.02% (0.21025) | 96.49th | v3 (v2023.03.01) |
| Nov 5, 2023 | 52.70% (0.52704) | 97.22th | v3 (v2023.03.01) |
| Oct 5, 2023 | 59.38% (0.59384) | 97.35th | v3 (v2023.03.01) |
| May 28, 2023 | 71.13% (0.71125) | 97.56th | v3 (v2023.03.01) |
| May 8, 2023 | 76.42% (0.76418) | 97.68th | v3 (v2023.03.01) |
| Apr 18, 2023 | 78.17% (0.78175) | 97.70th | v3 (v2023.03.01) |
| Mar 7, 2023 | 82.21% (0.82212) | 97.78th | v3 (v2023.03.01) |
| Mar 6, 2023 | 49.78% (0.49778) | 98.71th | v2 (v2022.01.01) |
| Aug 22, 2022 | 49.78% (0.49778) | 98.61th | v2 (v2022.01.01) |
| Feb 4, 2022 | 52.50% (0.52497) | 98.36th | v2 (v2022.01.01) |
| Feb 3, 2022 | 23.95% (0.23953) | 95.04th | v1 |
| Jan 6, 2022 | 23.95% (0.23953) | 94.98th | v1 |
| Sep 1, 2021 | 23.95% (0.23953) | 98.08th | v1 |
| May 5, 2021 | 23.95% (0.23953) | 0.00th | v1 |
| Apr 14, 2021 | 22.39% (0.22393) | 0.00th | v1 |
Weaknesses (1)
References (15)
- http://openwall.com/lists/oss-security/2017/11/25/1 x_refsource_MISCMailing List
- http://openwall.com/lists/oss-security/2017/11/25/2 x_refsource_MISCMailing List
- http://openwall.com/lists/oss-security/2017/11/25/3 x_refsource_MISCMailing List
- http://www.openwall.com/lists/oss-security/2021/05/04/7 mailing-listx_refsource_MLIST
- http://www.securitytracker.com/id/1039872 vdb-entryx_refsource_SECTRACKThird Party AdvisoryVDB Entry
- https://access.redhat.com/security/cve/CVE-2017-16943 Vendor Advisory
- https://bugs.exim.org/show_bug.cgi?id=2199 x_refsource_MISCExploitIssue Tracking
- https://bugzilla.redhat.com/show_bug.cgi?id=1517680 Issue Tracking
- https://git.exim.org/exim.git/commit/4090d62a4b25782129cc1643596dc2f6e8f63bde x_refsource_MISCPatch
- https://git.exim.org/exim.git/commitdiff/4e6ae6235c68de243b1c2419027472d7659aa2b4 x_refsource_MISCPatch
- https://github.com/LetUsFsck/PoC-Exploit-Mirror/tree/master/CVE-2017-16944 x_refsource_MISCExploit
- https://lists.exim.org/lurker/message/20171125.034842.d1d75cac.en.html x_refsource_MISCMailing List
- https://nvd.nist.gov/vuln/detail/CVE-2017-16943
- https://www.cve.org/CVERecord?id=CVE-2017-16943
- https://www.debian.org/security/2017/dsa-4053 vendor-advisoryx_refsource_DEBIANThird Party Advisory
Change history (0)
No recorded changes yet.
Sources
CVE.org / MITRE
Status PUBLISHED
Assigner mitre
Published Nov 25, 2017
Updated Aug 5, 2024
Reserved Nov 25, 2017
Link CVE-2017-16943
CISA Vulnrichment
Updated n/a