ExtremeXOS Privilege Escalation via Symlink Following in File Utilities

published 2026-07-20 3 mo ago modified 2026-10-24 15 d ago also EUVD-2026-46048

cvss: 8.7; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 46%
public exploits: 0; none known

The mv, cp, and rm file utilities exposed within the ExtremeXOS (EXOS) shell environment fail to safely canonicalize paths and follow symbolic links outside of the intended privilege boundary. An attacker with low-privilege CLI access can create a symbolic link that references a privileged filesystem location and then invoke the affected utilities to read, modify, or replace security-critical files outside of their authorized scope. Under certain conditions, this may enable escalation to root-level access and persistent modification of the device software stack. Exploitation is possible remotely by an attacker holding a low-privilege account, or locally via the serial console.

Extreme would like to thank Hadrien Barral (Université Gustave Eiffel) and Georges-Axel Jaloyan (French Ministry of the Interior) for responsible disclosure of their findings.

Patch / fix

fixed in 1

Extreme Networks Switch Engine (EXOS) 31.7.4, 32.7.4.15, 33.1.100, 33.7.1

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 3 mo ago (2026-07-20)

Exploit prediction

0.56% chance of exploitation in the next 30 days, higher than 46% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	8.7	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA	4.0	8.7	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

Extreme Networks Switch Engine (EXOS)

Classification

Weakness

CWE-59 Improper Link Resolution Before File Access

References

extremenetworks.com /support/policies/product-security

Sources

CVE List CVE-2026-8170
NVD CVE-2026-8170

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary