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No exploitation reportedFix available

CVE-2021-38189

No exploitation reported by the sources we read.

  • Published2021-08-08
  • Fixed in0.10.0-rc.3 · 0.9.6
  • WeaknessCWE-77

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

An issue was discovered in the lettre crate before 0.9.6 for Rust. In an e-mail message body, an attacker can place a . character after two <CR><LF> sequences and then inject arbitrary SMTP commands.

Timeline

dates in UTC
  1. 2021-08-0806:15CVE publishedNVD

Versions per branch

OSV · NVD
Lettre
BranchAffectedFixed in
0.10≥ 0.10.0-alpha.1, < 0.10.0-rc.30.10.0-rc.3
0.9< 0.9.60.9.6
0.x≥ 0.7.0, < 0.9.60.9.6
0.10= 0.10.0no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. Update Lettre to 0.10.0-rc.3 · 0.9.6

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVSS 3.19.8read 2026-10-23
  • NVDCVSS 2.07.5read 2026-10-23
  • NVDweakness (CWE)CWE-77read 2026-10-23
  • FIRST EPSSEPSS score1.5 %2026-11-09
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryCRITICAL2021-06-01

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2021-08-08
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-qc36-q22q-cjw3

Frequently asked questions

What is CVE-2021-38189?

An issue was discovered in the lettre crate before 0.9.6 for Rust. In an e-mail message body, an attacker can place a . character after two <CR><LF> sequences and then inject arbitrary SMTP commands.

Is CVE-2021-38189 actively exploited?

Active exploitation of CVE-2021-38189 has not been confirmed. Its EPSS score was 1.5% on 2026-11-09, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-38189?

CVE-2021-38189 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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