# lettre (crates.io) vulnerabilities

Source: https://junglewise.ai/threats/technologies/crates-io-lettre  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Updated: 9 November 2026, 03:07 UTC. Rebuilt every hour.  
Data: https://junglewise.ai/threats/technologies/crates-io-lettre.json  
License: CC BY 4.0 with a link back

Junglewise Threat Intelligence has tracked 3 vulnerabilities in lettre (crates.io): 0 in the last 7 days and 0 in the last 90 days, 1 of them critical and 0 exploited in the wild. The most recent, CVE-2026-46428, was published on 20 July 2026.

## Counts

- Last 7 days: 0
- Last 30 days: 0
- Last 90 days: 0
- All time: 3 (1 critical, 0 exploited in the wild)

## About lettre (crates.io)

Rust library for composing and sending email messages via SMTP and other transports.

## Latest lettre (crates.io) vulnerabilities

- [CVE-2026-46428: lettre TLS hostname verification bypass in boring-tls backend](https://junglewise.ai/threats/cve-2026-46428-lettre-tls-hostname-verification-bypass-in-boring-tls-backend) (critical, CVSS 4, published 20 Jul 2026)
- [CVE-2021-38189: RUSTSEC-2021-0069 - SMTP command injection in body](https://junglewise.ai/threats/cve-2021-38189-smtp-command-injection-in-lettre) (low, CVSS 3.1, published 22 May 2021)
- [CVE-2020-28247: RUSTSEC-2020-0069 - Argument injection in sendmail transport](https://junglewise.ai/threats/cve-2020-28247-argument-injection-in-lettre) (low, CVSS 3.1, published 11 Nov 2020)

## Most severe lettre (crates.io) vulnerabilities

- [CVE-2026-46428: lettre TLS hostname verification bypass in boring-tls backend](https://junglewise.ai/threats/cve-2026-46428-lettre-tls-hostname-verification-bypass-in-boring-tls-backend) (critical, CVSS 4, published 20 Jul 2026)
- [CVE-2020-28247: RUSTSEC-2020-0069 - Argument injection in sendmail transport](https://junglewise.ai/threats/cve-2020-28247-argument-injection-in-lettre) (low, CVSS 3.1, published 11 Nov 2020)
- [CVE-2021-38189: RUSTSEC-2021-0069 - SMTP command injection in body](https://junglewise.ai/threats/cve-2021-38189-smtp-command-injection-in-lettre) (low, CVSS 3.1, published 22 May 2021)

## Vulnerabilities per week

Nothing was published in the last eight weeks.

| Week of | Vulns | Critical | Exploited |
| --- | --- | --- | --- |
| 17 Aug 2026 | 0 | 0 | 0 |
| 24 Aug 2026 | 0 | 0 | 0 |
| 31 Aug 2026 | 0 | 0 | 0 |
| 7 Sep 2026 | 0 | 0 | 0 |
| 14 Sep 2026 | 0 | 0 | 0 |
| 21 Sep 2026 | 0 | 0 | 0 |
| 28 Sep 2026 | 0 | 0 | 0 |
| 5 Oct 2026 | 0 | 0 | 0 |
| 12 Oct 2026 | 0 | 0 | 0 |
| 19 Oct 2026 | 0 | 0 | 0 |
| 26 Oct 2026 | 0 | 0 | 0 |
| 2 Nov 2026 | 0 | 0 | 0 |
| 9 Nov 2026 | 0 | 0 | 0 |

## Other crates.io technologies

- [surrealdb (crates.io)](https://junglewise.ai/threats/technologies/surrealdb): 83 vulnerabilities
- [wasmtime (crates.io)](https://junglewise.ai/threats/technologies/wasmtime): 67 vulnerabilities
- [deno (crates.io)](https://junglewise.ai/threats/technologies/deno): 39 vulnerabilities
- [zebrad (crates.io)](https://junglewise.ai/threats/technologies/zebrad): 27 vulnerabilities
- [russh (crates.io)](https://junglewise.ai/threats/technologies/crates-io-russh): 26 vulnerabilities
- [openssl-src (crates.io)](https://junglewise.ai/threats/technologies/openssl-src): 26 vulnerabilities
- [openssl (crates.io)](https://junglewise.ai/threats/technologies/crates-io-openssl): 25 vulnerabilities
- [rustfs (crates.io)](https://junglewise.ai/threats/technologies/rustfs): 25 vulnerabilities
- [coreutils (crates.io)](https://junglewise.ai/threats/technologies/crates-io-coreutils): 21 vulnerabilities
- [ckb (crates.io)](https://junglewise.ai/threats/technologies/ckb): 19 vulnerabilities
- [apollo-router (crates.io)](https://junglewise.ai/threats/technologies/apollo-router): 13 vulnerabilities
- [deepseek-tui (crates.io)](https://junglewise.ai/threats/technologies/deepseek-tui): 13 vulnerabilities

## Sources

NVD, GitHub Security Advisories, OSV, the CISA Known Exploited Vulnerabilities catalog, FIRST EPSS and vendor advisories. Rebuilt every hour. Cite as: Junglewise Threat Intelligence, "lettre (crates.io) vulnerabilities", https://junglewise.ai/threats/technologies/crates-io-lettre, 9 November 2026.