{"id":"CVE-2026-86143","title":"In xmlIO in libxml2 before 2.15.4, an inconsistency in xmlOutputWriteCallback and xmlBufUse causes negative lengths to reach write callbacks, aka a lack of a check for integer overflow before calling writecallback","summary":"In xmlIO in libxml2 before 2.15.4, an inconsistency in xmlOutputWriteCallback and xmlBufUse causes negative lengths to reach write callbacks, aka a lack of a check for integer overflow before calling writecallback. This has security rele…","severity":"medium","cvss":6.9,"cvssVector":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L","cwe":["CWE-192","CWE-190"],"vendor":"xmlsoft","product":"libxml2","affected":["libxml2 < 2.15.4"],"patched":["libxml2 2.15.4"],"published":"2026-09-05","updated":"2026-09-15","sourceUpdated":"2026-09-15T19:31:15.857","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-86143","references":[{"url":"https://github.com/GNOME/libxml2/commit/90f293ba74d28b1d570920382e707586f68ebf35","label":"cve@mitre.org"},{"url":"https://github.com/GNOME/libxml2/compare/v2.15.3...v2.15.4","label":"cve@mitre.org"},{"url":"https://gitlab.gnome.org/GNOME/libxml2/-/work_items/1111","label":"cve@mitre.org"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-86143.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-86143"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2528987"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-86143"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-86143"},{"url":"https://access.redhat.com/errata/RHSA-2026:64463"},{"url":"https://access.redhat.com/errata/RHSA-2026:71586"},{"url":"https://access.redhat.com/errata/RHSA-2026:71641"},{"url":"https://access.redhat.com/errata/RHSA-2026:71585"},{"url":"https://access.redhat.com/errata/RHSA-2026:72475"},{"url":"https://access.redhat.com/errata/RHSA-2026:72476"},{"url":"https://access.redhat.com/errata/RHSA-2026:72470"},{"url":"https://access.redhat.com/errata/RHSA-2026:79357"},{"url":"https://access.redhat.com/errata/RHSA-2026:89759"},{"url":"https://access.redhat.com/errata/RHSA-2026:89750"},{"url":"https://access.redhat.com/errata/RHSA-2026:82939"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"epss":0.00194,"epssPercentile":0.08959,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-09-08T18:05:53.926972Z"},"ingestedAt":"2026-09-06T02:48:38.999Z","slug":"CVE-2026-86143","body":"## Overview\n\nIn xmlIO in libxml2 before 2.15.4, an inconsistency in xmlOutputWriteCallback and xmlBufUse causes negative lengths to reach write callbacks, aka a lack of a check for integer overflow before calling writecallback. This has security relevance for many types of uses of that length value within a callback.\n\n## Affected\n\n- `libxml2 < 2.15.4`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `libxml2 2.15.4`\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat OpenShift Container Platform 4 · updated 2026-10-26 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-86143.json)\n- **RHSA-2026:64463** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-06 · [advisory](https://access.redhat.com/errata/RHSA-2026:64463)\n- **RHSA-2026:71586** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) · released 2026-09-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:71586)\n- **RHSA-2026:71641** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 8), Red Hat Enterprise Linux BaseOS (v. 8) · released 2026-09-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:71641)\n- **RHSA-2026:71585** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9) · released 2026-09-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:71585)\n- **RHSA-2026:72475** · Red Hat · fixed in: Cert Manager support for Red Hat OpenShift release 1.20 · released 2026-09-28 · [advisory](https://access.redhat.com/errata/RHSA-2026:72475)\n- **RHSA-2026:72476** · Red Hat · fixed in: Cert Manager support for Red Hat OpenShift release 1.20 · released 2026-09-28 · [advisory](https://access.redhat.com/errata/RHSA-2026:72476)\n- **RHSA-2026:72470** · Red Hat · fixed in: Cert Manager support for Red Hat OpenShift release 1.20 · released 2026-09-28 · [advisory](https://access.redhat.com/errata/RHSA-2026:72470)\n- **RHSA-2026:79357** · Red Hat · fixed in: Red Hat Cost Management On-Premise 1 · released 2026-10-08 · [advisory](https://access.redhat.com/errata/RHSA-2026:79357)\n- **RHSA-2026:89759** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux BaseOS EUS (v. 10.0), Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) · released 2026-10-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:89759)\n- **RHSA-2026:89750** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream E4S (v.9.4), Red Hat Enterprise Linux BaseOS E4S (v.9.4) · released 2026-10-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:89750)\n- **RHSA-2026:82939** · Red Hat · fixed in: Red Hat Update Infrastructure 5 · released 2026-10-14 · [advisory](https://access.redhat.com/errata/RHSA-2026:82939)","depth":"sunlit","depthScore":38,"depthScoreParts":{"impact":38,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}