OESA-2026-3670

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Source
https://www.openeuler.org/en/security/security-bulletins/detail/?id=openEuler-SA-2026-3670
Import Source
https://repo.openeuler.org/security/data/osv/OESA-2026-3670.json
JSON Data
https://api.osv.dev/v1/vulns/OESA-2026-3670
Upstream
Published
2026-09-05T15:03:46Z
Modified
2026-09-05T15:16:35Z
Severity
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
Summary
expat security update
Details

expat is a stream-oriented XML parser library written in C. expat excels with files too large to fit RAM, and where performance and flexibility are crucial.

Security Fix(es):

Expat through 2.8.3 contains a denial of service vulnerability caused by quadratic algorithmic complexity in the storeAtts() function in xmlparse.c, where processing N specified attributes with non-normalized values triggers an O(N^2) linear scan of elementType->defaultAtts to determine CDATA status. A remote unauthenticated attacker can supply a single well-formed XML document of a few megabytes to an application parsing untrusted XML to cause excessive CPU consumption, resulting in denial of service without requiring authentication, external entity resolution, or non-default parser options.(CVE-2026-66046)

Expat through 2.8.3 contains an out-of-bounds read vulnerability that allows attackers to trigger memory corruption by processing XML with external entity parsers created via XML_ExternalEntityParserCreate. A struct size mismatch between ELEMENT_TYPE members causes storeAtts to read the attIndex member past allocated memory boundaries, resulting in failure to normalize whitespace in non-CDATA attributes or a wild pointer dereference causing a segfault. This vulnerability was introduced by the fix for CVE-2026-66046.(CVE-2026-76641)

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.(CVE-2026-76957)

Database specific 
{
    "severity": "High"
}
References

Affected packages

openEuler:22.03-LTS-SP4 / expat

Package

Name
expat
Purl
pkg:rpm/openEuler/expat&distro=openEuler-22.03-LTS-SP4

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
2.4.1-31.oe2203sp4

Ecosystem specific 

{
    "aarch64": [
        "expat-2.4.1-31.oe2203sp4.aarch64.rpm",
        "expat-debuginfo-2.4.1-31.oe2203sp4.aarch64.rpm",
        "expat-debugsource-2.4.1-31.oe2203sp4.aarch64.rpm",
        "expat-devel-2.4.1-31.oe2203sp4.aarch64.rpm"
    ],
    "noarch": [
        "expat-help-2.4.1-31.oe2203sp4.noarch.rpm"
    ],
    "src": [
        "expat-2.4.1-31.oe2203sp4.src.rpm"
    ],
    "x86_64": [
        "expat-2.4.1-31.oe2203sp4.x86_64.rpm",
        "expat-debuginfo-2.4.1-31.oe2203sp4.x86_64.rpm",
        "expat-debugsource-2.4.1-31.oe2203sp4.x86_64.rpm",
        "expat-devel-2.4.1-31.oe2203sp4.x86_64.rpm"
    ]
}

Database specific

source 
"https://repo.openeuler.org/security/data/osv/OESA-2026-3670.json"