CVE-2020-10531Network attack vector

Code execution via overflowing UnicodeString append length

Published Mar 12, 2020 · Updated Aug 4, 2024

Heap-based buffer overflow in ICU for C/C++ 66.1 and earlier allows remote attackers to execute code through a crafted string. UnicodeString::doAppend in common/unistr.cpp adds oldLength and srcLength in a signed 32-bit value without checking overflow, so a wrapped length permits an undersized allocation and heap overwrite. Exploitation requires an application to process an attacker-controlled string and user interaction; success crashes the process or runs code in its security context.

CVSS severity8.8
High
EPSS probability2.67%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in ICU for C/C++ 66.1 and earlier allows remote attackers to execute code through a crafted string. UnicodeString::doAppend in common/unistr.cpp adds oldLength and srcLength in a signed 32-bit value without checking overflow, so a wrapped length permits an undersized allocation and heap overwrite. Exploitation requires an application to process an attacker-controlled string and user interaction; success crashes the process or runs code in its security context.

The record

CVE
CVE-2020-10531
Published
Mar 12, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-190, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 12, 2020CVE 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8IBM X-ForceCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.8Amazon LinuxCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.8Oracle LinuxCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.8UbuntuCVSS:3.1/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.

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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-190Integer Overflow or Wraparound
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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