CVE-2022-25315 – CVE-2022-25315 is an integer overflow vulnerabi... (How to Fix)

Q: What is the severity of CVE-2022-25315?

CVE-2022-25315 has a CVSS score of 9.8 (CRITICAL). CVE-2022-25315 is an integer overflow vulnerability in Expat's storeRawNames function that can lead to heap buffer overflow. This allows attackers to potentially execute arbitrary code or cause denial of service. Any system or application using vulnerable versions of libexpat is affected.

📋 TL;DR

CVE-2022-25315 is an integer overflow vulnerability in Expat's storeRawNames function that can lead to heap buffer overflow. This allows attackers to potentially execute arbitrary code or cause denial of service. Any system or application using vulnerable versions of libexpat is affected.

💻 Affected Systems

Products:

Expat (libexpat)
Applications using libexpat library
Various Linux distributions
Embedded systems with XML parsing

Versions: All versions before 2.4.5

Operating Systems: Linux, Unix-like systems, Windows, Embedded OS

Default Config Vulnerable: ⚠️ Yes

Notes: Vulnerability triggers when parsing malicious XML input; many applications use Expat by default for XML processing

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution leading to complete system compromise, data theft, or ransomware deployment

🟠

Likely Case

Denial of service through application crashes, potentially leading to service disruption

🟢

If Mitigated

Application crash with limited impact if proper sandboxing and privilege separation are implemented

🌐 Internet-Facing: HIGH - Expat is widely used in web servers and XML parsers exposed to untrusted input

🏢 Internal Only: MEDIUM - Internal applications processing XML from untrusted sources remain vulnerable

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: LIKELY

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Proof of concept available in security advisories; exploitation requires sending malicious XML to vulnerable parser

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 2.4.5 and later

Vendor Advisory: https://github.com/libexpat/libexpat/pull/559

Restart Required: Yes

Instructions:

1. Update libexpat to version 2.4.5 or later using your package manager. 2. For Linux: 'sudo apt update && sudo apt upgrade libexpat1' (Debian/Ubuntu) or 'sudo yum update expat' (RHEL/CentOS). 3. Recompile any statically linked applications with patched library. 4. Restart affected services.

🔧 Temporary Workarounds

Input validation and sanitization

all

Implement strict XML input validation and size limits before parsing

Network filtering

all

Block or filter XML input at network perimeter for vulnerable services

🧯 If You Can't Patch

Isolate vulnerable systems in network segments with strict access controls
Implement application sandboxing and privilege reduction for XML processing components

🔍 How to Verify

Check if Vulnerable:

Check libexpat version: 'expat --version' or 'strings /usr/lib/libexpat.so | grep -i expat'

Check Version:

expat --version 2>/dev/null || strings $(ldconfig -p | grep libexpat | head -1 | awk '{print $4}') 2>/dev/null | grep -i 'expat.*version'

Verify Fix Applied:

Verify version is 2.4.5 or higher: 'expat --version' should show 2.4.5+

📡 Detection & Monitoring

Log Indicators:

Application crashes with segmentation faults
Unexpected process termination of XML parsers
Memory corruption errors in application logs

Network Indicators:

Unusually large XML payloads
Malformed XML structures in network traffic
Multiple connection attempts to XML endpoints

SIEM Query:

source="application.logs" AND ("segmentation fault" OR "SIGSEGV" OR "heap corruption") AND process="*xml*"

📊 Metadata

CVE ID: CVE-2022-25315

CVSS v3 Score: 9.8 (CRITICAL)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE: CWE-190

Published: February 18, 2022

Last Updated: May 5, 2025

🔗 References

http://www.openwall.com/lists/oss-security/2022/02/19/1 Mailing List,Third Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-484086.pdf Third Party Advisory
https://github.com/libexpat/libexpat/pull/559 Exploit,Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/03/msg00007.html Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3UFRBA3UQVIQKXTBUQXDWQOVWNBKLERU/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Y27XO3JMKAOMQZVPS3B4MJGEAHCZF5OM/
https://security.gentoo.org/glsa/202209-24 Third Party Advisory
https://security.netapp.com/advisory/ntap-20220303-0008/ Third Party Advisory
https://www.debian.org/security/2022/dsa-5085 Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.html Patch,Third Party Advisory
http://www.openwall.com/lists/oss-security/2022/02/19/1 Mailing List,Third Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-484086.pdf Third Party Advisory
https://github.com/libexpat/libexpat/pull/559 Exploit,Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/03/msg00007.html Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3UFRBA3UQVIQKXTBUQXDWQOVWNBKLERU/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Y27XO3JMKAOMQZVPS3B4MJGEAHCZF5OM/
https://security.gentoo.org/glsa/202209-24 Third Party Advisory
https://security.netapp.com/advisory/ntap-20220303-0008/ Third Party Advisory
https://www.debian.org/security/2022/dsa-5085 Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.html Patch,Third Party Advisory

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