CVE-2021-42911

highpriority · track · 40EPSS 0.035 · 89 %ileEURUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

3.52% (89th) EPSS

CVSS 7.5 · high

Is it mine?

7 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · fstec_bdu · nvd

EPSS · scored 2026-10-27

A Format String vulnerability exists in DrayTek Vigor 2960 <= 1.5.1.3, DrayTek Vigor 3900 <= 1.5.1.3, and DrayTek Vigor 300B <= 1.5.1.3 in the mainfunction.cgi file via a crafted HTTP message containing malformed QUERY STRING, which could let a remote malicious user execute arbitrary code.

cvss

Technical severity, 0–10. One row per scoring source.

9.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · high–critical · 7.5–9.8

v2.07.5highAV:N/AC:L/Au:N/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 10 · impact 6.4

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 5.9

v3.19.8criticalAV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · FSTEC (BDU) RU

v3.19criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-134USprimaryCWE-134US

affected products (7)

Products and version ranges known to be affected.

n/a n/a≤ n/aenisa_euvdEU
DrayTek Vigor 2960≤ 1.5.1.3fstec_bduRU
DrayTek Vigor 3900≤ 1.5.1.3fstec_bduRU
DrayTek Vigor300B≤ 1.5.1.3fstec_bduRU
draytek vigor2960 firmware≤ 1.5.1.3nvdUScpe:2.3:o:draytek:vigor2960_firmware:*:*:*:*:*:*:*:*
draytek vigor300b firmware≤ 1.5.1.3nvdUScpe:2.3:o:draytek:vigor300b_firmware:*:*:*:*:*:*:*:*
draytek vigor3900 firmware≤ 1.5.1.3nvdUScpe:2.3:o:draytek:vigor3900_firmware:*:*:*:*:*:*:*:*

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu nvd NVD CVE.org MITRE

published 2022-03-29modified 2026-06-17

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+776 more

references (5)

External citations — patches, advisories, analysis.

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