CVE-2021-38189

CVE-2021-38189 is a critical-severity vulnerability in Lettre with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-77.

Key facts

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.

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.
How severe is CVE-2021-38189?
CVE-2021-38189 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-38189 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (71st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-38189?
CVE-2021-38189 primarily affects Lettre. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-38189?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-38189 published?
CVE-2021-38189 was published on 2021-08-08 and last updated on 2026-06-17.

References

Affected products (12)

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