CVE-2026-4211 | D-Link DNS-1550-04 local_backup_mgr.cgi Local_Backup_Info stack-based overflow

Exp

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.

Published: 2026-03-16 Last update: 2026-03-19 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-4211 is rated Exploit Available (51.1/100): CVSS High severity, with low exploitation likelihood (EPSS 0.06%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2026-4211

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2026-4211

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-17 0.04% 0.06% +0.01%
2 2026-03-16 — 0.04% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-4211

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.4 4.0 HIGH
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/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 Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:N)
No additional preconditions are required beyond normal reachability.
Privileges required (PR:L)
Low privileges are required.
User interaction (UI:N)
No user interaction is required.
Vulnerable system confidentiality impact (VC:H)
High confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:H)
High integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:H)
High availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:N)
No confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:N)
No integrity impact on subsequent systems.
Subsequent system availability impact (SA:N)
No availability impact on subsequent systems.
Exploit maturity (threat) (E:P)
Proof-of-concept: public PoC exists; no reported exploitation and no known simplification tools.
Confidentiality requirement (CR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Integrity requirement (IR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Availability requirement (AR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Modified attack vector (MAV:X)
Not defined: scoring uses the Base Attack Vector (AV).
Modified attack complexity (MAC:X)
Not defined: scoring uses the Base Attack Complexity (AC).
Modified attack requirements (MAT:X)
Not defined: scoring uses the Base Attack Requirements (AT).
Modified privileges required (MPR:X)
Not defined: scoring uses the Base Privileges Required (PR).
Modified user interaction (MUI:X)
Not defined: scoring uses the Base User Interaction (UI).
Modified vulnerable system confidentiality impact (MVC:X)
Not defined: scoring uses the Base VC metric.
Modified vulnerable system integrity impact (MVI:X)
Not defined: scoring uses the Base VI metric.
Modified vulnerable system availability impact (MVA:X)
Not defined: scoring uses the Base VA metric.
Modified subsequent system confidentiality impact (MSC:X)
Not defined: scoring uses the Base SC metric.
Modified subsequent system integrity impact (MSI:X)
Not defined: scoring uses the Base SI metric.
Modified subsequent system availability impact (MSA:X)
Not defined: scoring uses the Base SA metric.
Safety (supplemental) (S:X)
Not evaluated.
Automatable (supplemental) (AU:X)
Not evaluated.
Recovery (supplemental) (R:X)
Not evaluated.
Value density (supplemental) (V:X)
Not evaluated.
Vulnerability response effort (supplemental) (RE:X)
Not evaluated.
Provider urgency (supplemental) (U:X)
Not evaluated.
 — — [email protected]
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 [email protected]
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]
9.0 2.0 HIGH
AV:N/AC:L/Au:S/C:C/I:C/A:C Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:C)
Complete confidentiality impact.
Integrity impact (I:C)
Complete integrity impact.
Availability impact (A:C)
Complete availability impact.
 8.0 10.0 [email protected]

Weakness enumeration for CVE-2026-4211

Affected software / configurations for CVE-2026-4211

Vendor Product Version Raw CPE
dlink dnr-202l_firmware <= 2026-02-05 cpe:2.3:o:dlink:dnr-202l_firmware:*:*:*:*:*:*:*:*
dlink dnr-326_firmware <= 2026-02-05 cpe:2.3:o:dlink:dnr-326_firmware:*:*:*:*:*:*:*:*
dlink dns-1100-4_firmware <= 2026-02-05 cpe:2.3:o:dlink:dns-1100-4_firmware:*:*:*:*:*:*:*:*
dlink dns-120_firmware <= 2026-02-05 cpe:2.3:o:dlink:dns-120_firmware:*:*:*:*:*:*:*:*
dlink dns-1200-05_firmware <= 2026-02-05 cpe:2.3:o:dlink:dns-1200-05_firmware:*:*:*:*:*:*:*:*
dlink dns-1550-04_firmware <= 2026-02-05 cpe:2.3:o:dlink:dns-1550-04_firmware:*:*:*:*:*:*:*:*
dlink dns-315l_firmware <= 2026-02-05 cpe:2.3:o:dlink:dns-315l_firmware:*:*:*:*:*:*:*:*
dlink dns-320_firmware <= 2026-02-05 cpe:2.3:o:dlink:dns-320_firmware:*:*:*:*:*:*:*:*
dlink dns-320l_firmware <= 2026-02-05 cpe:2.3:o:dlink:dns-320l_firmware:*:*:*:*:*:*:*:*
dlink dns-320lw_firmware <= 2026-02-05 cpe:2.3:o:dlink:dns-320lw_firmware:*:*:*:*:*:*:*:*
dlink dns-321_firmware <= 2026-02-05 cpe:2.3:o:dlink:dns-321_firmware:*:*:*:*:*:*:*:*
dlink dns-322l_firmware <= 2026-02-05 cpe:2.3:o:dlink:dns-322l_firmware:*:*:*:*:*:*:*:*
dlink dns-323_firmware <= 2026-02-05 cpe:2.3:o:dlink:dns-323_firmware:*:*:*:*:*:*:*:*
dlink dns-325_firmware <= 2026-02-05 cpe:2.3:o:dlink:dns-325_firmware:*:*:*:*:*:*:*:*
dlink dns-326_firmware <= 2026-02-05 cpe:2.3:o:dlink:dns-326_firmware:*:*:*:*:*:*:*:*
dlink dns-327l_firmware <= 2026-02-05 cpe:2.3:o:dlink:dns-327l_firmware:*:*:*:*:*:*:*:*
dlink dns-340l_firmware <= 2026-02-05 cpe:2.3:o:dlink:dns-340l_firmware:*:*:*:*:*:*:*:*
dlink dns-343_firmware <= 2026-02-05 cpe:2.3:o:dlink:dns-343_firmware:*:*:*:*:*:*:*:*
dlink dns-345_firmware <= 2026-02-05 cpe:2.3:o:dlink:dns-345_firmware:*:*:*:*:*:*:*:*
dlink dns-726-4_firmware <= 2026-02-05 cpe:2.3:o:dlink:dns-726-4_firmware:*:*:*:*:*:*:*:*

References for CVE-2026-4211

URL Tags
https://github.com/wudipjq/my_vuln/blob/main/D-Link8/vuln_160/160.md Exploit Third Party Advisory
https://vuldb.com/?ctiid.351122 Permissions Required VDB Entry
https://vuldb.com/?id.351122 Third Party Advisory VDB Entry
https://vuldb.com/?submit.770441 Third Party Advisory VDB Entry
https://www.dlink.com/ Product
cvelogic Threat Intelligence