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Vulnerability record · CVE-2021-3517 · published 19 May 2021

CVE-2021-3517: Xmlsoft libxml2 out-of-bounds write vulnerability

Xmlsoft · Libxml2

There is a flaw in the xml entity encoding functionality of libxml2 in versions before 2.9.11. An attacker who is able to supply a crafted file to be processed by an application linked with the affected functionality of libxml2 could trigger an out-of-bounds read. The most likely impact of this flaw is to application availability, with some potential impact to confidentiality and integrity if an attacker is able to use memory information to further exploit the application.

8.6 CVSS 3.1 High EPSS 17% · top 3.0% CWE-787 · Out-of-bounds writeCWE-125 · Out-of-bounds read
8.6CVSS 3.1 base score, v2 7.5
17%EPSS exploitation probability, 30 days
NoNot in CISA KEV
28Affected product versions listed by NVD
26References
17 Jun 2026Last modified by NVD

Description

There is a flaw in the xml entity encoding functionality of libxml2 in versions before 2.9.11. An attacker who is able to supply a crafted file to be processed by an application linked with the affected functionality of libxml2 could trigger an out-of-bounds read. The most likely impact of this flaw is to application availability, with some potential impact to confidentiality and integrity if an attacker is able to use memory information to further exploit the application.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H

Affected products

28 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://bugzilla.redhat.com/show_bug.cgi?id=1954232 Issue TrackingPatchThird Party Advisory
https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.ap
https://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.ap
https://lists.debian.org/debian-lts-announce/2021/05/msg00008.html Mailing ListThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BZOMV5J4PMZAORVT64BKLV6
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QVM4UJ3376I6ZVOYMHBNX4G
https://security.gentoo.org/glsa/202107-05 Third Party Advisory
https://security.netapp.com/advisory/ntap-20210625-0002/ Third Party Advisory
https://security.netapp.com/advisory/ntap-20211022-0004/ Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.html PatchThird Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.html PatchThird Party Advisory
https://www.oracle.com/security-alerts/cpujul2022.html Not Applicable
https://www.oracle.com/security-alerts/cpuoct2021.html PatchThird Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1954232 Issue TrackingPatchThird Party Advisory
https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.ap
https://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.ap
https://lists.debian.org/debian-lts-announce/2021/05/msg00008.html Mailing ListThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BZOMV5J4PMZAORVT64BKLV6
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QVM4UJ3376I6ZVOYMHBNX4G
https://security.gentoo.org/glsa/202107-05 Third Party Advisory
https://security.netapp.com/advisory/ntap-20210625-0002/ Third Party Advisory
https://security.netapp.com/advisory/ntap-20211022-0004/ Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.html PatchThird Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.html PatchThird Party Advisory
https://www.oracle.com/security-alerts/cpujul2022.html Not Applicable
https://www.oracle.com/security-alerts/cpuoct2021.html PatchThird Party Advisory

Track CVE-2021-3517 inside VULONE

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Source: NIST National Vulnerability Database (record CVE-2021-3517), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.