CVE-2021-0255Junos OS: ethtraceroute Local Privilege Escalation vulnerability in SUID binaries
- 5.5MediumCVSS base score
- 0.21%Exploitation in 30 daysEPSS · top 88% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
A local privilege escalation vulnerability in ethtraceroute of Juniper Networks Junos OS may allow a locally authenticated user with shell access to escalate privileges and write to the local filesystem as root. ethtraceroute is shipped with setuid permissions enabled and is owned by the root user, allowing local users to run ethtraceroute with root privileges. This issue affects Juniper Networks Junos OS: 15.1X49 versions prior to 15.1X49-D240; 17.3 versions prior to 17.3R3-S11, 17.4 versions prior to 17.4R3-S4; 18.1 versions prior to 18.1R3-S12; 18.2 versions prior to 18.2R3-S7; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R2-S7; 19.1 versions prior to 19.1R1-S6, 19.1R2-S2, 19.1R3-S4; 19.3 versions prior to 19.3R3-S2; 19.4 versions prior to 19.4R3-S1; 20.1 versions prior to 20.1R2, 20.1R3; 20.2 versions prior to 20.2R2-S1, 20.2R3; 20.3 versions prior to 20.3R1-S1.
Timeline
ID reserved
By juniper
- 6 months later
· 6 months later
Published
- 3 years later
· 3 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| juniperCNA (assigner) | 3.1 | Medium5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N |
| NVDNVD · Modified | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.21% · top 88% of all CVEs (13 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.5.
Affected products
- affected 15.1X49 – < 15.1X49-D240
- affected 17.3 – < 17.3R3-S11
- affected 17.4 – < 17.4R3-S4
- affected 18.1 – < 18.1R3-S12
- affected 18.2 – < 18.2R3-S7
- affected 18.3 – < 18.3R3-S4
- affected 18.4 – < 18.4R2-S7
- affected 19.1 – < 19.1R1-S6, 19.1R2-S2, 19.1R3-S4
- affected 19.3 – < 19.3R3-S2
- affected 19.4 – < 19.4R3-S1
- affected 20.1 – < 20.1R2, 20.1R3
- affected 20.2 – < 20.2R2-S1, 20.2R3
- affected 20.3 – < 20.3R1-S1
What to do
Solution: The following software releases have been updated to resolve this specific issue: Junos OS 15.1X49-D240, 17.3R3-S11, 17.4R3-S4, 18.1R3-S12, 18.2R3-S7, 18.4R2-S7, 19.1R1-S6, 19.1R2-S2, 19.1R3-S4, 19.3R3-S2, 19.4R3-S1, 20.1R2, 20.1R3, 20.2R2-S1, 20.2R3, 20.3R1-S1, 21.1R1, and all subsequent releases. As a proactive measure to tighten the security of other Ethernet OAM utilities, setuid was also removed from other binaries, including ethping, ethdm, ethslm and ethlm.
Workaround: To reduce the risk of malicious exploitation, use access lists or firewall filters to limit CLI access to the device only from trusted, administrative networks or hosts. Additionally, limit access to the Junos OS shell to only trusted system administrators.
Exploitation: Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
References
References1
- https://kb.juniper.net/JSA11175 (opens in a new tab)x_refsource_MISCx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2021-2874 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2021-0255)Record last updated .