CVE-2010-3870

What it is

The utf8_decode function in PHP before 5.3.4 does not properly handle non-shortest form UTF-8 encoding and ill-formed subsequences in UTF-8 data, which makes it easier for remote attackers to bypass cross-site scripting (XSS) and SQL injection protection mechanisms via a crafted string.

At a glance

Exploitability

Can be exploited over the network without logging in. Limited direct impact.

Exploit odds

11.3% chance of exploitation in the next 30 days (EPSS). Higher than most.

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2010-11-12 21:00 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-16 23:23 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 11.3% in the next 30 days (EPSS).
• Severity: 6.8 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2010-11-12 21:00 UTC

Last modified

2026-06-16 23:23 UTC

Exploit probability

11.3% · EPSS, next 30 days

Weakness

CWE-20 · Improper input validation

Record status

Modified

Affected

• PHP < 5.2.14
• PHP < 5.3.4
• Canonical Ubuntu Linux 6.06
• Canonical Ubuntu Linux 8.04
• Canonical Ubuntu Linux 9.10
• Canonical Ubuntu Linux 10.04
• Canonical Ubuntu Linux 10.10

Attack profile CVSS 2.0 · 6.8

Attack vector

Network

Complexity

Medium

Authentication

None

Confidentiality

Partial

Integrity

Partial

Availability

Partial

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2010-3870.md and follow it. Check whether this project is affected by CVE-2010-3870. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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