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ExploitedNot in CISA KEV yet

CVE-2021-3297

Exploitation confirmed. First attested on 2025-08-19 by GCVE · kevintel, GCVE · shadowserver.

  • Published2021-01-26
  • WeaknessCWE-287

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

On Zyxel NBG2105 V1.00(AAGU.2)C0 devices, setting the login cookie to 1 provides administrator access.

Timeline

dates in UTC
  1. 2021-01-2618:16CVE publishedNVD
  2. 2025-08-1911:59Listed as exploited by GCVEGCVE
  3. 2025-08-1911:59Exploitation first reportedGCVE

Observed activity

isMalicious corpus · updated 2026-11-04 03:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-3297?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-3297?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Zyxel nbg2105 firmwareversion to verify
BranchAffectedFixed in
1.0= v1.00\(aagu.2\)c0no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Advisories and patches

Detection

read 2026-11-03 22:42 UTC
Nuclei template
available
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
2021-01-26
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-vqr2-c24p-rh7p

Frequently asked questions

What is CVE-2021-3297?

On Zyxel NBG2105 V1.00(AAGU.2)C0 devices, setting the login cookie to 1 provides administrator access.

Is CVE-2021-3297 actively exploited?

Active exploitation of CVE-2021-3297 has not been confirmed. Its EPSS score was 20.5% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-3297?

CVE-2021-3297 has a CVSS v3 base score of 7.8 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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Same product first, then the same vendor advisory and the same publication week.

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Sources for this record