What is CVE-2026-4211?

CVE-2026-4211 is a high-severity vulnerability in D-Link Dnr-202l, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 8.8/10. Published 2026-03-16.

How severe is CVE-2026-4211?

High severity. CVSS v3 base score is 8.8 out of 10.

Buffer overflow in D-Link Dnr-202l

CVE-2026-4211

A weakness has been identified in D-Link DNS-120, DNR-202L, DNS-315L, DNS-320, DNS-320L, DNS-320LW, DNS-321, DNR-322L, DNS-323, DNS-325, DNS-326, DNS-327L, DNR-326, DNS-340L, DNS-343, DNS-345, DNS-726-4, DNS-1100-4, DNS-1200-05 and DNS-1550-04 up to 20260205. Affected by this issue is the function Local_Backup_Info of the file /cgi-bin/local_backup_mgr.cgi. This manipulation of the argument f_idx causes stack-based buffer overflow. The attack can be initiated remotely. The exploit has been made available to the public and could be used for attacks.

Vulnerability class: Buffer Overflow

Published 2026-03-16 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.015 (73.1th percentile), scored 2026-10-19.

Low probability of exploitation in the next 30 days, but still tracked. 73rd percentile — 73.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.015 · change: +0.007

Affected products

D-Link Dnr-202l — versions 20260205
D-Link Dnr-322l — versions 20260205
D-Link Dnr-326 — versions 20260205
D-Link Dns-1100-4 — versions 20260205
D-Link Dns-120 — versions 20260205
D-Link Dns-1200-05 — versions 20260205
D-Link Dns-1550-04 — versions 20260205
D-Link Dns-315l — versions 20260205
D-Link Dns-320 — versions 20260205
D-Link Dns-320l — versions 20260205

Weakness classification (CWE)

References

vuldb.com/ (technical-description, VDB Entry, Third Party Advisory, vdb-entry)
vuldb.com/ (signature, Permissions Required, permissions-required, VDB Entry)
vuldb.com/ (VDB Entry, Third Party Advisory, third-party-advisory)
github.com/wudipjq/my_vuln/blob/main/D-Link8/vuln_160/160.md (Exploit, Third Party Advisory, exploit)
www.dlink.com/ (Product, product)

Frequently asked questions

What is CVE-2026-4211?: CVE-2026-4211 is a high-severity vulnerability in D-Link Dnr-202l, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 8.8/10. Published 2026-03-16.
How severe is CVE-2026-4211?: High severity. CVSS v3 base score is 8.8 out of 10.