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CVE-2026-12339

MEDIUM 6.9

Published 2026-08-10 · Last modified 2026-08-25

A Zip Slip vulnerability in the WebUI ISP Upgrade functionality allows arbitrary file write via a crafted archive containing directory traversal sequences. An authenticated administrator may overwrite arbitrary files on the system.Successful exploitation may allow arbitrary file to be overwritten on the underlying system, affecting system integrity and availability.

NO EXPLOITATION SIGNALS

No known exploitation, public exploit, or elevated probability at this time. Track for changes.

Exploitation likelihood

0.3%chance of exploitation in 30 days · 27th percentile

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

6.9CVSS 4.0 · MEDIUM

  • ConfidentialityNone
  • IntegrityHigh
  • AvailabilityLow

What an attacker needs

  • Access: Must sit on the same / adjacent network
  • Privileges: Requires an admin / high-privilege account
  • User interaction: No user interaction needed
  • Complexity: No special conditions — reliably repeatable
  • Requirements: No special attack requirements

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept & exploit code

Test against your own equipment

curl -s https://vulnpedia.com/cve/CVE-2026-12339/poc.jsonMachine-readable PoC index for this CVE (for automation).

Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-12339/poc.json

Affected

Vendors Tp Link Systems Inc.

Products Tl Mr6400 V5.3 Archer Mr600 V2 Archer Mr200 V7 Tl Mr6400 V8.0 Tl Mr150 V3.20 Tl Mr100 V3.20

Weakness (CWE)

  • CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVSS vector

CVSS:4.0/AV:A/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N

All CVSS metrics

  • MEDIUM 6.9 v4.0 · CNA Primary
    CVSS:4.0/AV:A/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N
  • MEDIUM 6.9 v4.0 · NVD Secondary
    CVSS:4.0/AV:A/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:L/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

Sources: NVD · CVE.org · EPSS