CVE-2026-34975: Plunk is an open-source email platform built on top of AWS SES

Q: How do I fix CVE-2026-34975?

plunk: upgrade to 0.8.0. Exact commands for each OS are on this page.

Q: Is CVE-2026-34975 being exploited?

CVE-2026-34975 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-34975 affect?

CVE-2026-34975 affects plunk. Severity is high (CVSS 8.5). Plunk is an open-source email platform built on top of AWS SES. Prior to 0.8.0, a CRLF header injection vulnerability was discovered in SESService.ts, where user-supplied values for from.name, subject, custom header keys/values, and attachm

Q: How urgent is CVE-2026-34975?

Priority 40/100. High severity; On your watchlist

This month

HIGH 8.5WATCHLISTUPGRADE

CVE-2026-34975 is a high-severity flaw (CVSS 8.5) affecting plunk. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Plunk is an open-source email platform built on top of AWS SES. Prior to 0.8.0, a CRLF header injection vulnerability was discovered in SESService.ts, where user-supplied values for from.name, subject, custom header keys/values, and attachment filenames were interpolated directly into raw MIME messages without sanitization. An authenticated API user could inject arbitrary email headers (e.g. Bcc, Reply-To) by embedding carriage return/line feed c

Why this priority

High severity
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	8.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.3% (top 77%)
CISA exploited list	No
Weakness	CWE-93
Published	2026-04-06
Last modified	2026-10-24

Publisher (CNA): GitHub, Inc. · Vendor: useplunk

Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-06 17:17 UTCPublished CVE record published
2026-10-24 13:10 UTCUpdated Record last modified

useplunk plunk UPGRADE

Affected: < 0.8.0

Fixed in: 0.8.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy plunk || rpm -q plunk || plunk --version

2. UPGRADE to 0.8.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade plunk

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade plunk

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Exact fixes by distribution

Fedora ELN · ntpd-rs · FIXED · 1.7.2-3.eln159 · FEDORA-2026-57e4a99310 · source

sudo dnf upgrade --advisory=FEDORA-2026-57e4a99310

Fedora 46 · moby-engine · FIXED · 29.9.2-2.fc46 · FEDORA-2026-4856be87b3 · source

sudo dnf upgrade --advisory=FEDORA-2026-4856be87b3

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

GitHub PoC: romain-deperne/CVE-2026-34975 (0 stars)

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-34975?

plunk: upgrade to 0.8.0. Exact commands for each OS are on this page.

Is CVE-2026-34975 being exploited?

CVE-2026-34975 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-34975 affect?

CVE-2026-34975 affects plunk. Severity is high (CVSS 8.5). Plunk is an open-source email platform built on top of AWS SES. Prior to 0.8.0, a CRLF header injection vulnerability was discovered in SESService.ts, where user-supplied values for from.name, subject, custom header keys/values, and attachm

How urgent is CVE-2026-34975?

Priority 40/100. High severity; On your watchlist

Software pages

AWS vulnerabilities

References

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