CVE-2021-39856 Adobe Acrobat Reader DC NTLMv2 SSO Information Disclosure via LoadFile

What is CVE-2021-39856?

CVE-2021-39856 is a medium-severity vulnerability in Adobe Acrobat, published on 29 Sep 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

Acrobat Reader DC ActiveX Control versions 2021.005.20060 (and earlier), 2020.004.30006 (and earlier) and 2017.011.30199 (and earlier) are affected by an Information Disclosure vulnerability. An unauthenticated attacker could leverage this vulnerability to obtain NTLMv2 credentials. Exploitation of this issue requires user interaction in that a victim must visit an attacker controlled web page.

Weakness: CWE-200

Which versions are affected by CVE-2021-39856?

It affects 4 products.

Products include Adobe Acrobat, Adobe Acrobat Dc, Adobe Acrobat Reader, Adobe Acrobat Reader Dc.

How do I fix CVE-2021-39856?

No fix has been published for CVE-2021-39856 yet. Limit exposure of the affected software until one is available.

Is CVE-2021-39856 being exploited?

There is no known exploitation of CVE-2021-39856 in the wild and no public exploit code.

Other vulnerabilities in Adobe Acrobat

• CVE-2021-28550 Adobe Acrobat and Reader Use-After-Free Exploited Critical 9.6
• CVE-2021-21017 Adobe Acrobat and Reader Heap-based Buffer Overflow Exploited High 8.8
• CVE-2014-0546 Adobe Reader and Acrobat Sandbox Bypass Exploited High 8.8
• CVE-2014-0496 Adobe Reader and Acrobat Use-After-Free Exploited High 8.8
• CVE-2013-3346 Adobe Reader and Acrobat Memory Corruption Exploited High 8.8

All Adobe Acrobat vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-p74c-qp2j-549x.