CVE-2020-27874Network attack vector

Remote code execution via WXAM bounds-check failure

Published Feb 10, 2021 · Updated Aug 4, 2024

Out-of-bounds memory access in Tencent WeChat 7.0.18 allows remote attackers to execute arbitrary code through crafted content. The WXAM Decoder fails to validate user-supplied data before accessing memory beyond the end of an allocated object. Exploitation requires the target to visit a malicious page or open a malicious file, and resulting code runs in the current WeChat process.

CVSS severity8.8
High
EPSS probability2.09%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds memory access in Tencent WeChat 7.0.18 allows remote attackers to execute arbitrary code through crafted content. The WXAM Decoder fails to validate user-supplied data before accessing memory beyond the end of an allocated object. Exploitation requires the target to visit a malicious page or open a malicious file, and resulting code runs in the current WeChat process.

The record

CVE
CVE-2020-27874
Published
Feb 10, 2021
Updated
Aug 4, 2024
Vendor
Tencent
Product
WeChat
Classifications
CWE-119, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 10, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=7.0.18

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Tencent · WeChatversion=7.0.18

Published CVSS scores

8.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.8Zero Day InitiativeCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8NVDAV:N/AC:M/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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