CVE
PLANET GS-5220-8P2T2S stack buffer overflow in web interface cookie handling
- Exploited
- No known exploitation
- Fix
- Fixed in 3.2412b261008
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 3.2412b261008.
- Published
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 26/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
The PLANET GS-5220-8P2T2S switch has a stack buffer overflow in its web interface, triggered by an oversized webstax_auth cookie. A remote attacker can send a crafted request without logging in, which can corrupt memory and may crash the device.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
PLANET GS-5220-8P2T2S (hardware version 3.0) firmware versions before 3.2412b261008 contains a stack-based buffer overflow vulnerability that allows unauthenticated attackers to corrupt stack memory by submitting an oversized webstax_auth HTTP Cookie value that is copied into a fixed-size stack buffer without length validation. Attackers can send a crafted unauthenticated HTTP request with an oversized cookie to overwrite the saved return address and corrupt stack memory, leading to memory corruption and potential denial of service on the device.
Who should check
Teams operating PLANET GS-5220-8P2T2S V3 (hardware version 3.0) switches with firmware before v3.2412b261022, including web management interface exposure
Read the source excerpt
“PLANET GS-5220-8P2T2S (hardware version 3.0) firmware versions before 3.2412b261008”
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure17/25No login or user action needed, reachable over the network without a login · Unknown: Advisories don't say whether default setups are affected
- Reach?/20Unknown. No tracked technology or package matched
- Severity9.3/10CVSS 9.3
- No patch0/5No signal
What would change the score
- Would score about 71 if added to CISA KEV
- Would score about 66 if CISA's SSVC rates exploitation active
- Would score about 31 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 3.2412b261008.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-109445 (PLANET GS-5220-8P2T2S Stack Buffer Overflow via webstax_auth Cookie), using the cve.now data below.
Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.
What cve.now has for CVE-2026-109445 (entry last updated 2026-11-13):
Affected:
- PLANET Technology Corp. PLANET GS-5220-8P2T2S: fixed in 3.2412b261008
Fixed versions: 3.2412b261008.
Conditions (all must be true for the bug to be hit):
- Hardware version 3.0 of PLANET GS-5220-8P2T2S (source: https://www.vulncheck.com/advisories/planet-gs-5220-8p2t2s-stack-buffer-overflow-via-webstax-auth-cookie)
- Firmware earlier than v3.2412b261008 (per VulnCheck's affected range) (source: https://www.vulncheck.com/advisories/planet-gs-5220-8p2t2s-stack-buffer-overflow-via-webstax-auth-cookie)
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
Attacker needs: network access, no login, no user action.
CISA KEV: CVE-2026-109445 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-109445 only. If you also check another CVE, look up its own KEV status; never assume it from this one.
How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.
Verify against the linked advisories before concluding, and cite the date you read each one:
- https://www.planet.com.tw/en/support/security-advisory/12
- https://www.vulncheck.com/advisories/planet-gs-5220-8p2t2s-stack-buffer-overflow-via-webstax-auth-cookie
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.
Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.
Entry: https://cve.now/CVE-2026-109445
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-109445"}.Timeline
- CVE published
- First seen by cve.now
- Posted on X by cve.now
Affected versions
- PLANET Technology Corp. PLANET GS-5220-8P2T2S
fixed in 3.2412b261008
Evidence 3
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Patch
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-109445
Is CVE-2026-109445 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
A stack buffer overflow in the webstax_auth cookie handling lets crafted input overwrite memory on the device's stack, corrupting it and overwriting a saved return address. The advisory describes this as memory corruption and potential denial of service, and it does not confirm remote code execution on the hardware.Source: vulncheck.com
Which versions are affected by CVE-2026-109445?
PLANET GS-5220-8P2T2S: before 3.2412b261008.Source: cve.now feed data
Am I affected, and how do I check?
The affected product is PLANET GS-5220-8P2T2S hardware version 3.0 running firmware earlier than v3.2412b261008. To check, look at the hardware version on the device label or system information page and compare the firmware version shown there with v3.2412b261008.Source: vulncheck.com
How do I fix CVE-2026-109445?
The facts provided do not name a fixed version or vendor patch identifier for this issue, so no specific upgrade target can be given. Check PLANET's support channels for a firmware update for the GS-5220-8P2T2S that is v3.2412b261008 or later.Source: vulncheck.com