# CVE-2026-107590: Out-of-bounds write vulnerability in QTextCodec iconv-based encoding impacts Qt

Status: published. Published: 2026-10-27. Updated: 2026-11-04.

An out-of-bounds write vulnerability in the Qt QTextCodec iconv-based encoding of the Qt 5 Compatibility APIs module (Qt Core in Qt 5 and earlier) impacts Qt. Under certain conditions, encoding text with QTextCodec may write outside an internal buffer. This can cause the application to crash and may affect data integrity.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: Qt) — https://codereview.qt-project.org/c/qt/qt5compat/+/762752

## Affected products and versions

- qt / Qt: ≥ 0; < 4.5.0 (unaffected, python); ≥ 4.5.0; ≤ 6.8.8 (affected, python); ≥ 6.9.0; ≤ 6.11.2 (affected, python). Source: CNA: Qt

## Severity and prioritization

- CVSS 4.0: 1.9 (low); CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N/E:U/R:U/RE:L/U:Green; source: CNA: Qt

- CISA KEV: No listing in collected sources

- EPSS: 0.12% as of 2026-11-04; percentile 1.83%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-787, CWE-131

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://wiki.qt.io/List_of_known_vulnerabilities_in_Qt_products#CVE-2026-107590: (CNA: Qt; vendor-advisory)

- https://codereview.qt-project.org/c/qt/qt5compat/+/762752 (CNA: Qt; patch)

## Provenance

- CNA: Qt: https://www.cve.org/CVERecord?id=CVE-2026-107590; retrieved 2026-11-04; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-107590; retrieved 2026-11-04; source updated Not reported

Revision: bb8bbfe6606d81aae19c2c24315c20cdda68867888eea31af69cde7d9a775857

Canonical: https://y2.dev/cve/CVE-2026-107590

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.