CVE-2020-28638: ask_password in Tomb 2.0 through 2.7 returns a warning when pinentry-curses is used and $DISPLAY is non-empty,

This week

CRITICAL 9.8REMOTEUPGRADE

CVE-2020-28638 is a critical-severity flaw (CVSS 9.8) affecting tomb. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

ask_password in Tomb 2.0 through 2.7 returns a warning when pinentry-curses is used and $DISPLAY is non-empty, causing affected users' files to be encrypted with "tomb {W] Detected DISPLAY, but only pinentry-curses is found." as the encryption key.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.7% (top 46%)
CISA exploited list	No
Weakness	CWE-287
Published	2020-11-13
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: dyne

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-11-13 21:15 UTCPublished CVE record published
2026-06-17 03:10 UTCUpdated Record last modified

dyne tomb UPGRADE

Affected: >= 2.0 and <= 2.7

Fixed in: newer than 2.7

Safe to downgrade to: a release before 2.0

1. Check installed version

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

2. UPGRADE to newer than 2.7 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade tomb

Note

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

3. If no update is available yet, DOWNGRADE to a release before 2.0 (Debian / Ubuntu)

apt-cache madison tomb sudo apt install tomb=<VERSION_BEFORE_2.0> sudo apt-mark hold tomb

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list tomb sudo dnf downgrade tomb-<VERSION_BEFORE_2.0> sudo dnf versionlock add tomb

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2020-28638?

tomb: upgrade to newer than 2.7. Exact commands for each OS are on this page.

Is CVE-2020-28638 being exploited?

CVE-2020-28638 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-2020-28638 affect?

CVE-2020-28638 affects tomb. Severity is critical (CVSS 9.8). ask_password in Tomb 2.0 through 2.7 returns a warning when pinentry-curses is used and $DISPLAY is non-empty, causing affected users' files to be encrypted with "tomb {W] Detected DISPLAY, but only pinentry-curses is found." as the encrypt

How urgent is CVE-2020-28638?

Priority 58/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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