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QSN-8910-1: libxml2 vulnerabilities

October 8, 2026

Summary

Several security issues were fixed in libxml2.

Details

Yirou Yang discovered that libxml2 incorrectly handled certain XML catalogs. If a user or automated system was tricked into processing a specially crafted XML catalog, an attacker could possibly use this issue to cause libxml2 to crash, resulting in a denial of service. (CVE-2026-76781)

It was discovered that libxml2 incorrectly handled certain large qualified names, leading to a heap-based buffer overflow. An attacker could possibly use this issue to cause libxml2 to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2026-86138)

It was discovered that libxml2 incorrectly handled escaping certain large URI strings. An attacker could possibly use this issue to cause libxml2 to use excessive resources, leading to a denial of service. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-86139)

Xudong Cao and Meng Xu discovered that libxml2 incorrectly handled certain large XPointer expressions, leading to a heap-based buffer overflow. An attacker could possibly use this issue to cause libxml2 to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2026-86142)

Xudong Cao and Meng Xu discovered that libxml2 did not check for integer overflows before passing output lengths to write callbacks. An attacker could possibly use this issue to cause an application using libxml2 to crash, resulting in a denial of service. (CVE-2026-86143)

It was discovered that libxml2 did not apply parser options, such as disabling network access, when processing XInclude directives under certain circumstances. An attacker could possibly use this issue to perform XML external entity injection or server-side request forgery attacks, or cause a denial of service. (CVE-2026-86144)

Affected QuantaStor releases

ReleasePlatformPackageExposureShipped versionFixed versionStatus
6.9.1.001Ubuntu 22.04 LTSlibxml2Externally-facing2.9.13+dfsg-1ubuntu0.142.9.13+dfsg-1ubuntu0.14Fixed in this release
6.9.1.001Ubuntu 22.04 LTSlibxml2-utilsInternally-facing2.9.13+dfsg-1ubuntu0.142.9.13+dfsg-1ubuntu0.14Fixed in this release
6.9.0.464Ubuntu 22.04 LTSlibxml2Externally-facing2.9.13+dfsg-1ubuntu0.142.9.13+dfsg-1ubuntu0.14Fixed in this release
6.9.0.464Ubuntu 22.04 LTSlibxml2-utilsInternally-facing2.9.13+dfsg-1ubuntu0.142.9.13+dfsg-1ubuntu0.14Fixed in this release
6.8.6.015Ubuntu 22.04 LTSlibxml2Externally-facing2.9.13+dfsg-1ubuntu0.122.9.13+dfsg-1ubuntu0.14Fixed by QuantaStor security update
6.8.6.015Ubuntu 22.04 LTSlibxml2-utilsInternally-facing2.9.13+dfsg-1ubuntu0.122.9.13+dfsg-1ubuntu0.14Fixed by QuantaStor security update
6.8.5.018Ubuntu 22.04 LTSlibxml2Externally-facing2.9.13+dfsg-1ubuntu0.122.9.13+dfsg-1ubuntu0.14Fixed by QuantaStor security update
6.8.5.018Ubuntu 22.04 LTSlibxml2-utilsInternally-facing2.9.13+dfsg-1ubuntu0.122.9.13+dfsg-1ubuntu0.14Fixed by QuantaStor security update
6.8.4.038Ubuntu 22.04 LTSlibxml2Externally-facing2.9.13+dfsg-1ubuntu0.122.9.13+dfsg-1ubuntu0.14Fixed by QuantaStor security update
6.8.4.038Ubuntu 22.04 LTSlibxml2-utilsInternally-facing2.9.13+dfsg-1ubuntu0.122.9.13+dfsg-1ubuntu0.14Fixed by QuantaStor security update
6.8.3.018Ubuntu 22.04 LTSlibxml2Externally-facing2.9.13+dfsg-1ubuntu0.122.9.13+dfsg-1ubuntu0.14Fixed by QuantaStor security update
6.8.3.018Ubuntu 22.04 LTSlibxml2-utilsInternally-facing2.9.13+dfsg-1ubuntu0.122.9.13+dfsg-1ubuntu0.14Fixed by QuantaStor security update
6.8.2.002Ubuntu 22.04 LTSlibxml2Externally-facing2.9.13+dfsg-1ubuntu0.122.9.13+dfsg-1ubuntu0.14Fixed by QuantaStor security update
6.8.2.002Ubuntu 22.04 LTSlibxml2-utilsInternally-facing2.9.13+dfsg-1ubuntu0.122.9.13+dfsg-1ubuntu0.14Fixed by QuantaStor security update
6.8.1.007Ubuntu 22.04 LTSlibxml2Externally-facing2.9.13+dfsg-1ubuntu0.122.9.13+dfsg-1ubuntu0.14Fixed by QuantaStor security update
6.8.1.007Ubuntu 22.04 LTSlibxml2-utilsInternally-facing2.9.13+dfsg-1ubuntu0.122.9.13+dfsg-1ubuntu0.14Fixed by QuantaStor security update
6.8.0.205Ubuntu 22.04 LTSlibxml2Externally-facing2.9.13+dfsg-1ubuntu0.122.9.13+dfsg-1ubuntu0.14Fixed by QuantaStor security update
6.8.0.205Ubuntu 22.04 LTSlibxml2-utilsInternally-facing2.9.13+dfsg-1ubuntu0.122.9.13+dfsg-1ubuntu0.14Fixed by QuantaStor security update

Internally-facing: only accessible when logged into the QuantaStor console/ssh as the qadmin administrative sudo user; generally lower priority. Externally-facing: part of a service the storage platform presents on the network (or the kernel), so potentially reachable over the network.

CVEs

CVE-2026-86144, CVE-2026-86142, CVE-2026-76781, CVE-2026-86138, CVE-2026-86139, CVE-2026-86143

References

https://ubuntu.com/security/notices/USN-8910-1

https://nvd.nist.gov/vuln/detail/CVE-2026-86144

https://nvd.nist.gov/vuln/detail/CVE-2026-86142

https://nvd.nist.gov/vuln/detail/CVE-2026-76781

https://nvd.nist.gov/vuln/detail/CVE-2026-86138

https://nvd.nist.gov/vuln/detail/CVE-2026-86139

https://nvd.nist.gov/vuln/detail/CVE-2026-86143

Update

Fixes marked Fixed by QuantaStor security update are applied by upgrading QuantaStor with security patches included (Upgrade Manager). Fixed package versions:

PlatformPackageVersion
bioniclibxml22.9.4+dfsg1-6.1ubuntu1.9+esm9
Ubuntu 20.04 LTSlibxml22.9.10+dfsg-5ubuntu0.20.04.10+esm6
Ubuntu 22.04 LTSlibxml22.9.13+dfsg-1ubuntu0.14
Ubuntu 24.04 LTSlibxml22.9.14+dfsg-1.3ubuntu3.10
resolutelibxml22.15.2+dfsg-0.1ubuntu0.3
trustylibxml22.9.1+dfsg1-3ubuntu4.13+esm13
xeniallibxml22.9.3+dfsg1-1ubuntu0.7+esm14