What it is
CVE-2019-16928 is an unauthenticated vulnerability affecting Exim. Exim 4.92 through 4.92.2 allows remote code execution, a different vulnerability than CVE-2019-15846. There is a heap-based buffer overflow in...
Vulnerability report
Exploited in the wild
Confirmed confidence
In CISA KEV
CVE-2019-16928
Exim Remote Code Execution
- Severity
- CVSS 9.8 · Critical
- Confidence
- Confirmed
- Exploit status
- Exploited in the wild
- EPSS
- 41.6%
- First observed
- —
- Last observed
- —
Decision summary
What security teams need to know first
Direct answers before the deeper technical record.
Is it exploited?
Yes. Previdian tracks this CVE as a known exploited vulnerability. Confidence is confirmed. Listed in CISA KEV.
Who is affected?
Exim.
What should we do?
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
Overview
Exim 4.92 through 4.92.2 allows remote code execution, a different vulnerability than CVE-2019-15846
Exim 4.92 through 4.92.2 allows remote code execution, a different vulnerability than CVE-2019-15846. There is a heap-based buffer overflow in string_vformat in string.c involving a long EHLO command.
- Published
- 27 Sep 2019
- Exploitation Reported
- 03 Mar 2022
- Attack vector
- Remote
- Complexity
- Low
- Privileges
- None
- User interaction
- None
Tags
cisa
CVE References
- CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2019-16928
- DSA-4536 debian.org · Vendor Advisory https://www.debian.org/security/2019/dsa-4536
- USN-4141-1 usn.ubuntu.com · Vendor Advisory https://usn.ubuntu.com/4141-1/
- FEDORA-2019-006dfc94cd lists.fedoraproject.org · Vendor Advisory https://lists.fedoraproject.org/archives/list/package-announce%40list...
- FEDORA-2019-e080507ba5 lists.fedoraproject.org · Vendor Advisory https://lists.fedoraproject.org/archives/list/package-announce%40list...
- FEDORA-2019-d778bd4137 lists.fedoraproject.org · Vendor Advisory https://lists.fedoraproject.org/archives/list/package-announce%40list...
- GLSA-202003-47 security.gentoo.org · Vendor Advisory https://security.gentoo.org/glsa/202003-47
- [oss-security] 20190928 Exim CVE-2019-16928 RCE using a heap-based buffer overflow openwall.com · Mailing List http://www.openwall.com/lists/oss-security/2019/09/28/1
- [oss-security] 20190928 Re: Exim CVE-2019-16928 RCE using a heap-based buffer overflow openwall.com · Mailing List http://www.openwall.com/lists/oss-security/2019/09/28/2
- [oss-security] 20190928 Re: Exim CVE-2019-16928 RCE using a heap-based buffer overflow openwall.com · Mailing List http://www.openwall.com/lists/oss-security/2019/09/28/3
- [oss-security] 20190929 Re: Exim CVE-2019-16928 RCE using a heap-based buffer overflow openwall.com · Mailing List http://www.openwall.com/lists/oss-security/2019/09/28/4
- 20190929 [SECURITY] [DSA 4536-1] exim4 security update seclists.org · Mailing List https://seclists.org/bugtraq/2019/Sep/60
- lists.exim.org/lurker/message/20190927.032457.c1044d4c.en.html lists.exim.org · CVE Record https://lists.exim.org/lurker/message/20190927.032457.c1044d4c.en.html
- bugs.exim.org/show_bug.cgi bugs.exim.org · CVE Record https://bugs.exim.org/show_bug.cgi?id=2449
- git.exim.org/exim.git/commit/478effbfd9c3cc5a627fc671d4bf... git.exim.org · CVE Record https://git.exim.org/exim.git/commit/478effbfd9c3cc5a627fc671d4bf94d1...
Exploitation evidence
Why Previdian marks this CVE as exploited
Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.
Exploited in the wild
CISA
A trusted third party reported exploitation.
Known exploited vulnerability sources
Per-source evidence links for KEV attestations are available through the Previdian Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| CISA First | 2022-03-03 00:00 UTC |
Detection
Operational artifacts and observed signals
Make the evidence actionable in scanner, SOC, and edge-control workflows.
Observed signals
- Request targets
- User-Agents
- Callback hosts
- 0
- 0
- 0
Request targets and User-Agents available in Pro. Callback host details available in Enterprise.
Scanner coverage
No scanner integrations recorded yet.
Virtual patch status
No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.
Learn about virtual patches →No detection artifacts or sensor request patterns are available for this CVE yet.
Check back as sensor telemetry and scanner integrations are updated.
Risk and context
Severity, weaknesses, and research context
CVSS v3.1
9.8
Critical
Potential damage if exploited. Separate from whether attackers are using it.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
41.6%
Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.
Weaknesses
All CVSS Scores
CVSS v3.1
9.8
Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v2.0
7.5
High
AV:N/AC:L/Au:N/C:P/I:P/A:P
Timeline
From disclosure to observed exploitation
-
00:00 UTC
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
20:07 UTC
CVE published
Vulnerability disclosed publicly
-
00:00 UTC
CVE ID reserved
Identifier reserved by the CNA
Pro API
Automate this intelligence
Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
- Evidence confidence and provenance
- First-party sensor telemetry
- PoC and scanner references
- Affected versions and enrichment
- Automation-ready JSON delivery
GET /api/v2/pro/kevs/CVE-2019-16928
Free JSON includes basic KEV fields{
"cve_id": "CVE-2019-16928",
"confidence": "Confirmed",
"cvss_score": 9.8,
"cvss_estimated": false,
"epss_score": 0.41638,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "attempts": 0, "sensors": 0 }
}