CVE-2026-124317

Description

libexpat through 2.10.0 contains an out-of-bounds read vulnerability in unknown_toUtf8() and unknown_toUtf16() in xmltok.c when handling application-registered unknown encodings. Attackers can supply a document ending in a truncated multibyte sequence so the convert callback reads past the parse buffer, leaking adjacent memory or crashing applications.

Overview

State: PUBLISHED
Assigner (CNA): VulnCheck
CVSS severity: MEDIUM
CVSS score: 6.3 / 10
CVSS vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N
Effective score: 6.3 / 10 MEDIUM source: CNA overview
CWE(s): CWE-126
Reserved: 2026-11-07
Published: 2026-11-07 14:17 UTC
Last updated: 2026-11-07 14:17 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/124xxx/CVE-2026-124317.json

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-119271

EUVD enrichment is queued; refresh the page in a few seconds.

Affected products (1)

Vendor	Product	Versions	Platforms
libexpat	libexpat	`0` (affected)	—

Vendor references (4)

References embedded in the original CVE record by the assigning CNA.

https://github.com/libexpat/libexpat/pull/1492 patchissue-tracking
https://github.com/libexpat/libexpat/blob/a70841d9ffa64ddde29ab824ed6305035ebe4c47/expat/lib/xmltok.c#L1274-L1322 technical-description
https://github.com/libexpat/libexpat product
VulnCheck Advisory: libexpat through 2.10.0 Out-of-Bounds Read via unknown_toUtf8 and unknown_toUtf16 third-party-advisory

Web references (0)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

No web references attached yet.

Remediations (10)

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Fortinet CISA KEV List 2026: Every Exploited CVE and Its Fix

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Microsoft Patch Tracker (November 2026): Exploit-Ranked | Senserva

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2026-11-08 11:18 UTC
SAP Security Patch Day - October 2026

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On 13 th of October 2026 , SAP security patch day saw the release of 16 new security notes and 4 GitHub security advisories. There are 2 updates to previously released security notes.

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[Security Advisory] September 2026 CVE Advisory Notification

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What you need to know: On September 24, 2026 , ServiceNow issued CVE - 2026 -86857, CVE - 2026 -86858, CVE - 2026 -13016, CVE - 2026 -86859, and CVE - 2026 -86860. Each of these security issues was identified through internal security testing, customer security assessments, or reports submitted through ServiceNow's responsible disclosure and bug bounty programs and was remediated independently. For security ...

2026-11-08 11:18 UTC
Oracle Critical Patch Update Advisory - July 2026

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2026-11-08 11:18 UTC
Oracle Critical Security Patch Update Advisory - September 2026

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2026-11-08 11:18 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-124317.json.

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:github/libexpat/libexpat",
          "product": "libexpat",
          "repo": "https://github.com/libexpat/libexpat",
          "vendor": "libexpat",
          "versions": [
            {
              "lessThanOrEqual": "2.10.0",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
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      ],
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            {
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                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "credits": [
        {
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          "type": "finder",
          "value": "O\u011fuzhan Demirba\u015f"
        },
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "Sebastian Pipping"
        }
      ],
      "datePublic": "2026-11-06T00:00:00.000Z",
      "descriptions": [
        {
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        }
      ],
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      "problemTypes": [
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          "descriptions": [
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      ],
      "title": "libexpat through 2.10.0 Out-of-Bounds Read via unknown_toUtf8 and unknown_toUtf16",
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    "dateReserved": "2026-11-07T12:27:50.865Z",
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  },
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}