CVE-2021-21017

mediumpriority · act · 90OT risk · criticalKEV · exploitedEPSS 0.863 · 100 %ileexploit · PoCEURUUS

grimoire priorityP0 · Act now

Exploitable?

Yes · in the wild

CISA KEV · 2 exploits · PoC

Likely / severe?

86.3% (100th) EPSS

CVSS 6.8 · medium

Is it mine?

16 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · fstec_bdu · nvd

added 2021-11-03remediate by 2021-11-17

required action Apply updates per vendor instructions.

EPSS · scored 2026-10-26

Adobe Acrobat and Reader Heap-based Buffer Overflow Vulnerability

Acrobat Reader DC versions versions 2020.013.20074 (and earlier), 2020.001.30018 (and earlier) and 2017.011.30188 (and earlier) are affected by a heap-based buffer overflow vulnerability. An unauthenticated attacker could leverage this vulnerability to achieve arbitrary code execution in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file.

cvss

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

8.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.8–8.8

v2.06.8mediumAV:N/AC:M/Au:N/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 8.6 · impact 6.4

v3.18.8highAV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:Hsecondary · FSTEC (BDU) RU

v3.18.8highCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:Hsecondary · ENISA EU

v3.18.8highCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:Hsecondary · psirt@adobe.comexploitability 2.8 · impact 5.9

v3.18.8highCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:Hsecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: active · Automatable: no · Technical Impact: totalcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-787USprimaryCWE-122USCWE-122USCWE-787US

ATT&CK techniques

ATT&CK techniques this enables or maps to.

T1204.002Malicious File — This exploit requires a user to open a malicious file. It can then result in execution of arbitrary code which could have any number of impacts.exploitation

exploits (2)

Public proof-of-concept and weaponised exploit code.

ZeusBox/CVE-2021-21017ZeusBox/CVE-2021-21017PoC · poc_in_github
tzwlhack/CVE-2021-21017tzwlhack/CVE-2021-21017PoC · poc_in_github

affected products (16)

Products and version ranges known to be affected.

Adobe Acrobat Reader≤ unspecified ≤2020.013.20074enisa_euvdEU
Adobe Acrobat Reader≤ unspecified ≤2020.001.30018enisa_euvdEU
Adobe Acrobat Reader≤ unspecified ≤2017.011.30188enisa_euvdEU
Adobe Acrobat Reader≤ unspecified ≤Noneenisa_euvdEU
Adobe Systems Inc. Adobe Acrobat 2017≤ 2017.011.30190 Classic 2017fstec_bduRU
Adobe Systems Inc. Adobe Acrobat 2020≤ 2020.001.30020 Classic 2020fstec_bduRU
Adobe Systems Inc. Adobe Acrobat Document Cloud≤ 2021.001.20135 Continuousfstec_bduRU
Adobe Systems Inc. Adobe Acrobat Reader 2017≤ 2017.011.30190 Classic 2017fstec_bduRU
Adobe Systems Inc. Adobe Acrobat Reader 2020≤ 2020.001.30020 Classic 2020fstec_bduRU
Adobe Systems Inc. Adobe Acrobat Reader Document Cloud≤ 2021.001.20135 Continuousfstec_bduRU
adobe acrobat17.0 → 17.011.30188nvdUScpe:2.3:a:adobe:acrobat:*:*:*:*:*:*:*:*
adobe acrobat20.0 → 20.001.30018nvdUScpe:2.3:a:adobe:acrobat:*:*:*:*:*:*:*:*
adobe acrobat dc≤ 20.013.20074nvdUScpe:2.3:a:adobe:acrobat_dc:*:*:*:*:*:*:*:*
adobe acrobat reader17.0 → 17.011.30188nvdUScpe:2.3:a:adobe:acrobat_reader:*:*:*:*:*:*:*:*
adobe acrobat reader20.0 → 20.001.300183nvdUScpe:2.3:a:adobe:acrobat_reader:*:*:*:*:*:*:*:*
adobe acrobat reader dc≤ 20.013.20074nvdUScpe:2.3:a:adobe:acrobat_reader_dc:*:*:*:*:*:*:*:*

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 2021-02-11modified 2026-06-17

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+16091 more

references (7)

External citations — patches, advisories, analysis.

scry

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