CVE-2026-32778

Process crash via zombie prefix lookup

Published Mar 16, 2026 · Updated Mar 16, 2026

NULL pointer dereference in Expat libexpat before 2.7.5 allows local users to crash a parsing process after memory exhaustion. In setContext, lookup creates a PREFIX entry before poolCopyString copies its name; a failed copy leaves name NULL, and a retry calls keyeq on that entry. The caller must induce an allocation failure and then retry parsing with the same initialized parser, limiting impact to interruption of the process using the library.

CVSS severity2.9
Low
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in Expat libexpat before 2.7.5 allows local users to crash a parsing process after memory exhaustion. In setContext, lookup creates a PREFIX entry before poolCopyString copies its name; a failed copy leaves name NULL, and a retry calls keyeq on that entry. The caller must induce an allocation failure and then retry parsing with the same initialized parser, limiting impact to interruption of the process using the library.

The record

CVE
CVE-2026-32778
Published
Mar 16, 2026
Updated
Mar 16, 2026
Vendor
Expat Project
Product
libexpat
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 16, 2026Record 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=0 <2.7.5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Expat Project · libexpatversion=0 <2.7.5

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
2.9MITRECVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Endpoint Denial of Service: Application or System Exploitation

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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