CVE-2026-56412
published 2026-06-21CVE-2026-56412: libexpat before 2.8.2 does not consider XML_TOK_DATA_CHARS in doCdataSection and thus lacks handler call depth tracking for various calls from within handlers…
PriorityP424medium5.9CVSS 3.1
AVLACLPRNUINSUCLILAL
EPSS
0.18%
7.4th percentile
libexpat before 2.8.2 does not consider XML_TOK_DATA_CHARS in doCdataSection and thus lacks handler call depth tracking for various calls from within handlers in cases of a policy violation. Thus, a use-after-free can occur. NOTE: this issue exists because of an incomplete fix for CVE-2026-50219.
Affected
13 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| ansible-automation-platform-26 | lightspeed-chatbot-rhel9 | — | — |
| ansible-automation-platform-27 | lightspeed-chatbot-rhel9 | — | — |
| debian | expat | — | — |
| debian | xmlrpc-c | — | — |
| exploit-intelligence-tech-preview | vulnerability-analysis-rhel9 | — | — |
| libexpat_project | libexpat | < 2.8.2 | 2.8.2 |
| libexpat_project | libexpat | < 2.8.4 | 2.8.4 |
| mozilla | firefox | — | — |
| mozilla | thunderbird | — | — |
| rhoai | odh-llama-stack-core-rhel9 | — | — |
| rhoai | odh-mlflow-rhel9 | — | — |
| rhoai | odh-trustyai-garak-lls-provider-dsp-rhel9 | — | — |
| ubuntu | expat | — | — |
CVSS provenance
nvdv3.15.9MEDIUMCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
vendor_ubuntu7.5HIGH
vendor_redhat5.9MEDIUM
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GHSA
libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks.
ghsa_unreviewed·2026-08-20·CVSS 5.9
CVE-2026-76957 [MEDIUM] CWE-416 libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks.
libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks. Thus, a use-after-free can occur. NOTE: this is similar to CVE-2026-50219, CVE-2026-56131 and CVE-2026-56412.
VulDB
libexpat up to 2.8.1 use after free (EUVD-2026-38189)
vuldb·2026-06-21·CVSS 4.9
CVE-2026-56412 [MEDIUM] libexpat up to 2.8.1 use after free (EUVD-2026-38189)
A vulnerability has been found in libexpat up to 2.8.1 and classified as critical. This affects an unknown part. Performing a manipulation results in use after free.
This vulnerability is reported as CVE-2026-56412. The attack requires a local approach. No exploit exists.
The affected component should be upgraded.
GHSA
libexpat before 2.8.2 does not consider XML_TOK_DATA_CHARS in doCdataSection and thus lacks handler call depth tracking for various calls from within handlers in cases of a policy violation.
ghsa_unreviewed·2026-06-21·CVSS 5.9
CVE-2026-56412 [MEDIUM] CWE-416 libexpat before 2.8.2 does not consider XML_TOK_DATA_CHARS in doCdataSection and thus lacks handler call depth tracking for various calls from within handlers in cases of a policy violation.
libexpat before 2.8.2 does not consider XML_TOK_DATA_CHARS in doCdataSection and thus lacks handler call depth tracking for various calls from within handlers in cases of a policy violation. Thus, a use-after-free can occur. NOTE: this issue exists because of an incomplete fix for CVE-2026-50219.
Ubuntu
Expat vulnerabilities
vendor_ubuntu·2026-09-21·CVSS 7.5
CVE-2026-50219 [HIGH] Expat vulnerabilities
Title: Expat vulnerabilities
Summary: Several security issues were fixed in Expat.
It was discovered that Expat could be made to allocate large amounts of
memory when parsing a small crafted document. An attacker could possibly
use this issue to cause Expat to consume resources, leading to a denial of
service. This issue was only addressed in Ubuntu 24.04 LTS.
(CVE-2025-59375)
It was discovered that Expat incorrectly handled empty external parameter
entity content. An attacker could possibly use this issue to cause Expat to
crash, resulting in a denial of service. (CVE-2026-32776)
It was discovered that Expat incorrectly handled certain DTD content. An
attacker could possibly use this issue to cause Expat to enter an infinite
loop, resulting in a denial of service. (CVE-2026-32777)
It
Red Hat
libexpat: libexpat: Memory corruption vulnerability allows arbitrary code execution or denial of service
vendor_redhat·2026-08-20·CVSS 5.9
CVE-2026-76957 [MEDIUM] CWE-825 libexpat: libexpat: Memory corruption vulnerability allows arbitrary code execution or denial of service
libexpat: libexpat: Memory corruption vulnerability allows arbitrary code execution or denial of service
libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks. Thus, a use-after-free can occur. NOTE: this is similar to CVE-2026-50219, CVE-2026-56131 and CVE-2026-56412.
A flaw was found in libexpat. The library's handling of custom encoding callbacks lacks proper tracking of handler call depth, which can lead to a use-after-free vulnerability. This memory corruption flaw could allow a local attacker to cause a denial of service or potentially execute arbitrary code.
Statement: Red Hat ships libexpat (packaged as "expat") across many products. All versions of expat prior to 2.8.4 are affected by this use-after-free vulnerability. Exploitation requires trig
Red Hat
libexpat: libexpat: Use-after-free vulnerability due to improper handling of XML CDATA sections
vendor_redhat·2026-06-21·CVSS 5.9
CVE-2026-56412 [MEDIUM] CWE-825 libexpat: libexpat: Use-after-free vulnerability due to improper handling of XML CDATA sections
libexpat: libexpat: Use-after-free vulnerability due to improper handling of XML CDATA sections
libexpat before 2.8.2 does not consider XML_TOK_DATA_CHARS in doCdataSection and thus lacks handler call depth tracking for various calls from within handlers in cases of a policy violation. Thus, a use-after-free can occur. NOTE: this issue exists because of an incomplete fix for CVE-2026-50219.
A flaw was found in libexpat. This vulnerability, present in versions before 2.8.2, stems from improper handling of XML CDATA sections, where the library fails to adequately track the depth of handler calls. This can result in a 'use-after-free' error, a type of memory corruption that could allow an attacker to crash the application or potentially gain unauthorized control.
Package: exploit-intellige
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-76957 expat: libexpat: Memory corruption vulnerability allows arbitrary code execution or denial of service [fedora-all]
bugzilla·2026-08-26·CVSS 5.9
CVE-2026-76957 [MEDIUM] CVE-2026-76957 expat: libexpat: Memory corruption vulnerability allows arbitrary code execution or denial of service [fedora-all]
CVE-2026-76957 expat: libexpat: Memory corruption vulnerability allows arbitrary code execution or denial of service [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks. Thus, a use-after-free can occur. NOTE: this is similar to CVE-2026-50219, CVE-2026-56131 and CVE-2026-56412.
Bugzilla
CVE-2026-76957 mingw-expat: libexpat: Memory corruption vulnerability allows arbitrary code execution or denial of service [fedora-all]
bugzilla·2026-08-26·CVSS 5.9
CVE-2026-76957 [MEDIUM] CVE-2026-76957 mingw-expat: libexpat: Memory corruption vulnerability allows arbitrary code execution or denial of service [fedora-all]
CVE-2026-76957 mingw-expat: libexpat: Memory corruption vulnerability allows arbitrary code execution or denial of service [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks. Thus, a use-after-free can occur. NOTE: this is similar to CVE-2026-50219, CVE-2026-56131 and CVE-2026-56412.
Bugzilla
CVE-2026-76957 libexpat: libexpat: Memory corruption vulnerability allows arbitrary code execution or denial of service
bugzilla·2026-08-20·CVSS 5.9
CVE-2026-76957 [MEDIUM] CVE-2026-76957 libexpat: libexpat: Memory corruption vulnerability allows arbitrary code execution or denial of service
CVE-2026-76957 libexpat: libexpat: Memory corruption vulnerability allows arbitrary code execution or denial of service
libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks. Thus, a use-after-free can occur. NOTE: this is similar to CVE-2026-50219, CVE-2026-56131 and CVE-2026-56412.
Bugzilla
CVE-2026-56412 mingw-expat: libexpat: Use-after-free vulnerability due to improper handling of XML CDATA sections [fedora-44]
bugzilla·2026-06-26·CVSS 5.9
CVE-2026-56412 [MEDIUM] CVE-2026-56412 mingw-expat: libexpat: Use-after-free vulnerability due to improper handling of XML CDATA sections [fedora-44]
CVE-2026-56412 mingw-expat: libexpat: Use-after-free vulnerability due to improper handling of XML CDATA sections [fedora-44]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Bugzilla
CVE-2026-56412 expat: libexpat: Use-after-free vulnerability due to improper handling of XML CDATA sections [fedora-44]
bugzilla·2026-06-26·CVSS 5.9
CVE-2026-56412 [MEDIUM] CVE-2026-56412 expat: libexpat: Use-after-free vulnerability due to improper handling of XML CDATA sections [fedora-44]
CVE-2026-56412 expat: libexpat: Use-after-free vulnerability due to improper handling of XML CDATA sections [fedora-44]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Bugzilla
CVE-2026-56412 mingw-expat: libexpat: Use-after-free vulnerability due to improper handling of XML CDATA sections [fedora-43]
bugzilla·2026-06-26·CVSS 5.9
CVE-2026-56412 [MEDIUM] CVE-2026-56412 mingw-expat: libexpat: Use-after-free vulnerability due to improper handling of XML CDATA sections [fedora-43]
CVE-2026-56412 mingw-expat: libexpat: Use-after-free vulnerability due to improper handling of XML CDATA sections [fedora-43]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Bugzilla
CVE-2026-56412 expat: libexpat: Use-after-free vulnerability due to improper handling of XML CDATA sections [fedora-43]
bugzilla·2026-06-26·CVSS 5.9
CVE-2026-56412 [MEDIUM] CVE-2026-56412 expat: libexpat: Use-after-free vulnerability due to improper handling of XML CDATA sections [fedora-43]
CVE-2026-56412 expat: libexpat: Use-after-free vulnerability due to improper handling of XML CDATA sections [fedora-43]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Bugzilla
CVE-2026-56412 libexpat: libexpat: Use-after-free vulnerability due to improper handling of XML CDATA sections
bugzilla·2026-06-21·CVSS 5.9
CVE-2026-56412 [MEDIUM] CVE-2026-56412 libexpat: libexpat: Use-after-free vulnerability due to improper handling of XML CDATA sections
CVE-2026-56412 libexpat: libexpat: Use-after-free vulnerability due to improper handling of XML CDATA sections
libexpat before 2.8.2 does not consider XML_TOK_DATA_CHARS in doCdataSection and thus lacks handler call depth tracking for various calls from within handlers in cases of a policy violation. Thus, a use-after-free can occur. NOTE: this issue exists because of an incomplete fix for CVE-2026-50219.
2026-06-21
Published