CVE-2020-26130: Issues were discovered in Open TFTP Server multithreaded 1.66 and Open TFTP Server single port 1.66

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HIGH 7.8DOWNGRADE

CVE-2020-26130 is a high-severity flaw (CVSS 7.8) affecting open tftp server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Issues were discovered in Open TFTP Server multithreaded 1.66 and Open TFTP Server single port 1.66. Due to insufficient access restrictions in the default installation directory, an attacker can elevate privileges by replacing the OpenTFTPServerMT.exe or the OpenTFTPServerSP.exe binary.

Why this priority

High severity
Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.4% (top 61%)
CISA exploited list	No
Weakness	CWE-732
Published	2020-10-28
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

2020-10-28 18:15 UTCPublished CVE record published
2026-06-17 03:07 UTCUpdated Record last modified

open tftp server project open tftp server DOWNGRADE

Affected: 1.66

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.66

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.66 (Debian / Ubuntu)

apt-cache madison open-tftp-server sudo apt install open-tftp-server=<VERSION_BEFORE_1.66> sudo apt-mark hold open-tftp-server

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list open-tftp-server sudo dnf downgrade open-tftp-server-<VERSION_BEFORE_1.66> sudo dnf versionlock add open-tftp-server

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-2020-26130?

open tftp server: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-26130 being exploited?

CVE-2020-26130 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-2020-26130 affect?

CVE-2020-26130 affects open tftp server. Severity is high (CVSS 7.8). Issues were discovered in Open TFTP Server multithreaded 1.66 and Open TFTP Server single port 1.66. Due to insufficient access restrictions in the default installation directory, an attacker can elevate privileges by replacing the OpenTFTP

How urgent is CVE-2020-26130?

Priority 42/100. High severity; Public exploit reference

Related CVEs

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-2018-10388 CRITICAL 9.8 UPGRADE Format string vulnerability in the logMess function in TFTP Server SP 1.66 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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