Libexpat up to 2.9.0 Lib/xmlparse.c StoreAtts integer overflow

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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5.5$0-$5k1.30+

Summaryinfo

A vulnerability was found in Libexpat up to 2.9.0 and classified as problematic. The impacted element is the function StoreAtts of the file Lib/xmlparse.c. Such manipulation leads to integer overflow. This vulnerability is documented as CVE-2026-118370. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in Libexpat up to 2.9.0 and classified as problematic. Affected by this issue is the function StoreAtts of the file Lib/xmlparse.c. The manipulation with an unknown input leads to a integer overflow vulnerability. Using CWE to declare the problem leads to CWE-190. The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. Impacted is availability. CVE summarizes:

libexpat through 2.9.0 contains a signed integer overflow vulnerability in storeAtts() in lib/xmlparse.c that allows attackers to trigger out-of-bounds writes via oversized attribute counts. Attackers can supply a multi-gigabyte document with a start tag carrying over 2^30 attributes to overflow attIndex and nPrefixes, crashing applications or corrupting heap memory.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-118370 since 10/28/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 10/28/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 5.6
VulDB Meta Temp Score: 5.5

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 5.9
CNA Vector (VulnCheck): 🔒

CVSSv2info

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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Integer overflow
CWE: CWE-190 / CWE-189
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

10/28/2026 Advisory disclosed
10/28/2026 +0 days CVE reserved
10/28/2026 +0 days VulDB entry created
10/28/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Not defined

CVE: CVE-2026-118370 (🔒)
GCVE (CVE): GCVE-0-2026-118370
GCVE (VulDB): GCVE-100-427676

Entryinfo

Created: 10/28/2026 03:48
Changes: 10/28/2026 03:48 (74)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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