CVE-2018-10388: Format string vulnerability in the logMess function in TFTP Server SP 1.66 and earlier allows remote attackers

Q: How do I fix CVE-2018-10388?

open tftp server: upgrade to newer than 1.66. Exact commands for each OS are on this page.

Q: Is CVE-2018-10388 being exploited?

CVE-2018-10388 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-2018-10388 affect?

CVE-2018-10388 affects open tftp server. Severity is critical (CVSS 9.8). Format string vulnerability in the logMess function in TFTP Server SP 1.66 and earlier allows remote attackers to perform a denial of service or execute arbitrary code via format string sequences in a TFTP error packet.

Q: How urgent is CVE-2018-10388?

Priority 62/100. Critical severity; EPSS top 9%: very likely to be exploited; Remotely exploitable, no login, no user action

This week

CRITICAL 9.8REMOTEUPGRADE

CVE-2018-10388 is a critical-severity flaw (CVSS 9.8) affecting open tftp server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Format string vulnerability in the logMess function in TFTP Server SP 1.66 and earlier allows remote attackers to perform a denial of service or execute arbitrary code via format string sequences in a TFTP error packet.

Why this priority

Critical severity
EPSS top 9%: very likely to be exploited
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	4.4% (top 9%)
CISA exploited list	No
Weakness	CWE-134
Published	2019-12-23
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: open tftp server project

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

Am I affected?

Timeline

2019-12-23 23:15 UTCPublished CVE record published
2026-06-17 01:33 UTCUpdated Record last modified

open tftp server project open tftp server UPGRADE

Affected: <= 1.66

Fixed in: newer than 1.66

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy open-tftp-server || rpm -q open-tftp-server || open-tftp-server --version

2. UPGRADE to newer than 1.66 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade open-tftp-server

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade open-tftp-server

Note

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

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-2018-10388?

open tftp server: upgrade to newer than 1.66. Exact commands for each OS are on this page.

Is CVE-2018-10388 being exploited?

CVE-2018-10388 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-2018-10388 affect?

CVE-2018-10388 affects open tftp server. Severity is critical (CVSS 9.8). Format string vulnerability in the logMess function in TFTP Server SP 1.66 and earlier allows remote attackers to perform a denial of service or execute arbitrary code via format string sequences in a TFTP error packet.

How urgent is CVE-2018-10388?

Priority 62/100. Critical severity; EPSS top 9%: very likely to be exploited; Remotely exploitable, no login, no user action

Related CVEs

CVE-2020-26130 HIGH 7.8 DOWNGRADE Issues were discovered in Open TFTP Server multithreaded 1.66 and Open TFTP Server single port 1.66
CVE-2019-12568 CRITICAL 9.8 UPGRADE Stack-based overflow vulnerability in the logMess function in Open TFTP Server SP 1.66 and earlier allows remo
CVE-2019-12567 CRITICAL 9.8 UPGRADE Stack-based overflow vulnerability in the logMess function in Open TFTP Server MT 1.65 and earlier allows remo
CVE-2018-10389 CRITICAL 9.8 UPGRADE Format string vulnerability in the logMess function in TFTP Server MT 1.65 and earlier allows remote attackers
CVE-2018-10387 CRITICAL 9.8 UPGRADE Heap-based overflow vulnerability in TFTP Server SP 1.66 and earlier allows remote attackers to perform a deni

References

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