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NVD / CVE Program· CNA Zyxel

CVE-2026-7273: A stack-based buffer overflow vulnerability in the CGI program of Zyxel GS1900-48HPv2 firmware versions through 2.90(ABTQ.1)C0 could allow a

Noroxi assessment

Priority: This week (action score 66/100)

  • CISA has confirmed exploitation in the wild (Sep 21, 2026). Remediation deadline for US federal agencies: Sep 24, 2026.
  • Probability of exploitation in the next 30 days: 2.7% (FIRST EPSS); higher than 86.2% of all records.
  • Someone on the same network segment can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to the record, no fixed version is available yet.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Don’t wait for the next maintenance window. Until a fix is released, restrict access to the affected component and follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · CISA KEV · FIRST EPSS

A stack-based buffer overflow vulnerability in the CGI program of Zyxel GS1900-48HPv2 firmware versions through 2.90(ABTQ.1)C0 could allow a LAN-based, unauthenticated attacker to exploit the flaw and potentially execute OS commands via a crafted HTTP request.

HighCVSS 8.8 · v3.1KEVWeaponized No fix recorded
Published
Jun 16, 2026
Updated
Oct 25, 2026
EPSS
2.7% · 86th percentile

Report tools

JSON

Action score

66

This week

Don’t wait for the next maintenance window.

CVSS
35 / 40 · 8.8 / 10
CISA KEV
30 / 30 · Listed
EPSS
1 / 30 · 2.7%

CISA SSVC decision

Exploitation
active
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Zyxel
8.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Actively exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on Sep 21, 2026. That signals real attacks, not theory.

Remediation deadline for US federal agencies: Sep 24, 2026.

Get told when this record changes

  • In CISA KEV: exploitation in the wild confirmed
  • Weaponized exploit exists
  • No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-7273

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
zyxelgs1900-8 firmware
zyxelgs1900-8
zyxelgs1900-8hp firmware
zyxelgs1900-8hp
zyxelgs1900-10hp firmware
zyxelgs1900-10hp
zyxelgs1900-16 firmware
zyxelgs1900-16
zyxelgs1900-24 firmware
zyxelgs1900-24
zyxelgs1900-24e firmware
zyxelgs1900-24e

and 8 more

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • zyxel gs1900-10hp firmwarebefore 2.90\(aazi.2\)c0
  • zyxel gs1900-16 firmwarebefore 2.90\(aahj.2\)c0
  • zyxel gs1900-24 firmwarebefore 2.90\(aahl.2\)c0
  • zyxel gs1900-24e firmwarebefore 2.90\(aahk.2\)c0
  • zyxel gs1900-24ep firmwarebefore 2.90\(abto.2\)c0
  • zyxel gs1900-24hpv2 firmwarebefore 2.90\(abtp.2\)c0
  • zyxel gs1900-48 firmwarebefore 2.90\(aahn.2\)c0
  • zyxel gs1900-48hpv2 firmwarebefore 2.90\(abtq.2\)c0
  • zyxel gs1900-8 firmwarebefore 2.90\(aahh.2\)c0
  • zyxel gs1900-8hp firmwarebefore 2.90\(aahi.2\)c0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Zyxel). Independent of NVD's CPE analysis and usually ahead of it.

  • Zyxel GS1900-10HP firmware

    • <= 2.90(AAZI.1)C0affected

  • Zyxel GS1900-16 firmware

    • <= 2.90(AAHJ.1)C0affected

  • Zyxel GS1900-24 firmware

    • <= 2.90(AAHL.1)C0affected

  • Zyxel GS1900-24E firmware

    • <= 2.90(AAHK.1)C0affected

  • Zyxel GS1900-24EP firmware

    • <= 2.90(ABTO.1)C0affected

  • Zyxel GS1900-24HPv2 firmware

    • <= 2.90(ABTP.1)C0affected

  • Zyxel GS1900-48 firmware

    • <= 2.90(AAHN.1)C0affected

  • Zyxel GS1900-48HPv2 firmware

    • <= 2.90(ABTQ.1)C0affected

  • Zyxel GS1900-8 firmware

    • <= 2.90(AAHH.1)C0affected

  • Zyxel GS1900-8HP firmware

    • <= 2.90(AAHI.1)C0affected

Same product

zyxel: all records

Other highest-scoring records for the same primary product.

  • CVE-2019-15800An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0.
    40Plan
  • CVE-2019-15803An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0.
    36Monitor
  • CVE-2019-15799An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0.
    36Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2022-45853May 30, 2023 · The privilege escalation vulnerability in the Zyxel GS1900-8 firmware version V2.70(AAHH.3) and the GS1900-8HP firmware version V2.70(AAHI
    26Monitor
  • ← EarlierCVE-2024-8881Nov 11, 2024 · A post-authentication command injection vulnerability in the CGI program in the Zyxel GS1900-48 switch firmware version V2.80(AAHN.1)C0 and
    27Monitor
  • ← EarlierCVE-2024-8882Nov 11, 2024 · A buffer overflow vulnerability in the CGI program in the Zyxel GS1900-48 switch firmware version V2.80(AAHN.1)C0 and earlier could allow an
    18Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. CISA KEV+97 d
  3. TodayOct 27, 2026+133 d
EPSS, last 120 days+1% in 7 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Someone on the same network segment can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Adjacent
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-121 · Stack-based Buffer Overflow

CVSS vector

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records