CVE-2020-0878: Microsoft Browser Memory Corruption Vulnerability
Noroxi assessment
Priority: This week (action score 60/100)
- CISA has confirmed exploitation in the wild (Nov 3, 2021); it is known to be used in ransomware campaigns. Remediation deadline for US federal agencies: May 3, 2022.
- A ready-made attack tool exists and the flaw can be exploited over the network without an account, so priority is at least “This week”.
- Probability of exploitation in the next 30 days: 2.6% (FIRST EPSS); higher than 85.8% of all records.
- Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. Special conditions such as timing or configuration are required.
- According to the record, no fixed version is available yet.
Don’t wait for the next maintenance window. Until a fix is released, restrict access to the affected component and follow the vendor's advisory.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · CISA KEV · FIRST EPSS
<p>A remote code execution vulnerability exists in the way that Microsoft browsers access objects in memory. The vulnerability could corrupt memory in a way that could allow an attacker to execute arbitrary code in the context of the current user. An attacker who successfully exploited the vulnerability could gain the same user rights as the current user. If the current user is logged on with administrative user rights, the attacker could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.</p> <p>An attacker could host a specially crafted website that is designed to exploit the vulnerability through Microsoft browsers, and then convince a user to view the website. The attacker could also take advantage of compromised websites, or websites that accept or host user-provided content or advertisements, by adding specially crafted content that could exploit the vulnerability. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically via an enticement in email or instant message, or by getting them to open an email attachment.</p> <p>The security update addresses the vulnerability by modifying how Microsoft browsers handle objects in memory.</p>
- Published
- Sep 11, 2020
- Updated
- Jun 16, 2026
- EPSS
- 2.6% · 85th percentile
- CWE
- CWE-787
Report tools
Action score
60
This week
Don’t wait for the next maintenance window.
- CVSS
- 16 / 40 · 4.2 / 10
- CISA KEV
- 30 / 30 · Listed
- EPSS
- 1 / 30 · 2.6%
- Ready-made attack tool
- 13 / 60 · floor: at least 60
CISA SSVC decision
- Exploitation
- active
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · microsoft
- 4.2
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N/E:P/RL:O/RC:C
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Actively exploited in the wild
CISA added this to its Known Exploited Vulnerabilities catalog on Nov 3, 2021. That signals real attacks, not theory.
Remediation deadline for US federal agencies: May 3, 2022.
Known to be used in ransomware campaigns.
Get told when this record changes
- In CISA KEV: exploitation in the wild confirmed
- Weaponized exploit exists
- No fixed version yet
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| microsoft | internet explorer | cpe:2.3:a:microsoft:internet_explorer |
| microsoft | windows 10 1507 | cpe:2.3:o:microsoft:windows_10_1507 |
| microsoft | windows 10 1607 | cpe:2.3:o:microsoft:windows_10_1607 |
| microsoft | windows 10 1709 | cpe:2.3:o:microsoft:windows_10_1709 |
| microsoft | windows 10 1803 | cpe:2.3:o:microsoft:windows_10_1803 |
| microsoft | windows 10 1809 | cpe:2.3:o:microsoft:windows_10_1809 |
| microsoft | windows 10 1903 | cpe:2.3:o:microsoft:windows_10_1903 |
| microsoft | windows 10 1909 | cpe:2.3:o:microsoft:windows_10_1909 |
| microsoft | windows 10 2004 | cpe:2.3:o:microsoft:windows_10_2004 |
| microsoft | windows 7 | cpe:2.3:o:microsoft:windows_7 |
| microsoft | windows 8.1 | cpe:2.3:o:microsoft:windows_8.1 |
| microsoft | windows rt 8.1 | cpe:2.3:o:microsoft:windows_rt_8.1 |
and 6 more
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- microsoft chakracoreall versions
- microsoft edgeall versions
- microsoft internet explorer11
- microsoft internet explorer9
Versions reported by the vendor
Affected version ranges reported by the assigning authority (microsoft). Independent of NVD's CPE analysis and usually ahead of it.
Microsoft ChakraCore
- before publicationaffected
Microsoft Internet Explorer 11
- 1.0.0 and later · before publicationaffected
Microsoft Internet Explorer 9
- 1.0.0 and later · before publicationaffected
Microsoft Microsoft Edge (EdgeHTML-based)
- 1.0..0 and later · before publicationaffected
Same product
microsoft: all recordsOther highest-scoring records for the same primary product.
- CVE-2014-1776Use-after-free vulnerability in Microsoft Internet Explorer 6 through 11 allows remote attackers to execute arbitrary code or cause a denialKEV94Now
- CVE-2010-0249Use-after-free vulnerability in Microsoft Internet Explorer 6, 6 SP1, 7, and 8 on Windows 2000 SP4; Windows XP SP2 and SP3; Windows Server 2KEV93Now
- CVE-2014-0322Use-after-free vulnerability in Microsoft Internet Explorer 9 and 10 allows remote attackers to execute arbitrary code via vectors involvingKEV91Now
Published before and after this one in the same product
- ← EarlierCVE-2020-1567Aug 17, 2020 · MSHTML Engine Remote Code Execution Vulnerability17Monitor
- ← EarlierCVE-2020-1570Aug 17, 2020 · Scripting Engine Memory Corruption Vulnerability33Monitor
- Later →CVE-2020-1012Sep 11, 2020 · WinINet API Elevation of Privilege Vulnerability36Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
Weaponized
A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- Published
- CISA KEV+417 d
- TodayOct 31, 2026+2241 d
No history yet (it accumulates with the daily EPSS job).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- A user must open a link or visit a page.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- low · data can be read
- Integrity
- low · data or configuration can be modified
- Availability
- none
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality impact
- Low
- Integrity impact
- Low
- Availability impact
- None
Weakness class (CWE)
CWE-787 · Out-of-bounds WriteCVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
Show all references (1 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.