{"answers":{"affected":"10 open source packages ship an affected version, including phpoffice/phpspreadsheet. It affects 1 product.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40296 exists.","fix":"Upgrade phpoffice/phpspreadsheet to a fixed version for your release line: 1.30.4, 2.1.16, 2.4.5 or 3.10.5.","what":"CVE-2026-40296 is a medium-severity cross-site scripting vulnerability in PHPOffice PhpSpreadsheet, published on 6 May 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2026-40296 and fix it if it is affected.\n\nWhat it is: CVE-2026-40296 is a medium-severity cross-site scripting vulnerability in PHPOffice PhpSpreadsheet, published on 6 May 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40296 exists.\n\nAffected packages and fixed versions:\n- phpoffice/phpspreadsheet (Packagist): affected all versions; fixed in 1.30.4\n- phpoffice/phpspreadsheet (Packagist): affected all versions; fixed in 1.30.4\n- phpoffice/phpspreadsheet (Packagist): affected from 2.0.0; fixed in 2.1.16\n- phpoffice/phpspreadsheet (Packagist): affected from 2.0.0; fixed in 2.1.16\n- phpoffice/phpspreadsheet (Packagist): affected from 2.2.0; fixed in 2.4.5\n- phpoffice/phpspreadsheet (Packagist): affected from 2.2.0; fixed in 2.4.5\n- phpoffice/phpspreadsheet (Packagist): affected from 3.3.0; fixed in 3.10.5\n- phpoffice/phpspreadsheet (Packagist): affected from 3.3.0; fixed in 3.10.5\n- phpoffice/phpspreadsheet (Packagist): affected from 4.0.0; fixed in 5.7.0\n- phpoffice/phpspreadsheet (Packagist): affected from 4.0.0; fixed in 5.7.0\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-40296/ (Markdown: https://insights.sbomify.com/CVE-2026-40296/index.md)","id":"CVE-2026-40296","markdown":"https://insights.sbomify.com/CVE-2026-40296/index.md","name":"CVE-2026-40296","record":{"aliases":["GHSA-hrmw-qprp-wgmc"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["code_execution"],"network_reachable":"yes","non_default_config":false,"product_category":"PHP spreadsheet library","requires_auth":"low_privilege","summary":"Attackers can achieve stored XSS by crafting spreadsheet cells with specific custom number formats that bypass HTML escaping during conversion.","user_interaction":"required","vuln_class":"xss"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"phpspreadsheet","vendor":"phpoffice"}],"cvss":{"score":5.4,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","version":"3.1"},"cwes":[{"id":"CWE-79","name":"Improper Neutralization of Input During Web Page Generation"}],"description":"PhpSpreadsheet is a pure PHP library for reading and writing spreadsheet files. The HTML writer skips htmlspecialchars escaping when a cell's formatted value differs from the original value. When a cell has a custom number format containing the text placeholder @ along with any additional literal characters (for example \". @\", \"@ \", or \"x@\"), the formatter replaces @ with the cell value and adds the extra characters, causing the formatted value to differ from the original and bypassing HTML escaping entirely. An attacker who can control the cell value and number format of an uploaded spreadsheet that is later converted to HTML and displayed to other users can achieve stored cross-site scripting. This issue is fixed in versions 5.7.0, 3.10.5, 2.4.5, 2.1.16, and 1.30.4.","ecosystems":["Packagist"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"PhpSpreadsheet vulnerable to XSS in HTML writer via custom number format codes","id":"CVE-2026-40296","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Packagist","product":null,"products":[],"type":"xss","year":"2026"},"n_packages":10,"n_references":1,"next":{"headline":"next-intl has an open redirect vulnerability","id":"CVE-2026-40299"},"packages":[{"ecosystem":"Packagist","fixed":["1.30.4"],"introduced":["0"],"last_affected":[],"package":"phpoffice/phpspreadsheet","purl":null,"source":"GHSA-hrmw-qprp-wgmc"},{"ecosystem":"Packagist","fixed":["1.30.4"],"introduced":["0"],"last_affected":[],"package":"phpoffice/phpspreadsheet","purl":"pkg:composer/phpoffice/phpspreadsheet","source":"GHSA-hrmw-qprp-wgmc"},{"ecosystem":"Packagist","fixed":["2.1.16"],"introduced":["2.0.0"],"last_affected":[],"package":"phpoffice/phpspreadsheet","purl":null,"source":"GHSA-hrmw-qprp-wgmc"},{"ecosystem":"Packagist","fixed":["2.1.16"],"introduced":["2.0.0"],"last_affected":[],"package":"phpoffice/phpspreadsheet","purl":"pkg:composer/phpoffice/phpspreadsheet","source":"GHSA-hrmw-qprp-wgmc"},{"ecosystem":"Packagist","fixed":["2.4.5"],"introduced":["2.2.0"],"last_affected":[],"package":"phpoffice/phpspreadsheet","purl":null,"source":"GHSA-hrmw-qprp-wgmc"},{"ecosystem":"Packagist","fixed":["2.4.5"],"introduced":["2.2.0"],"last_affected":[],"package":"phpoffice/phpspreadsheet","purl":"pkg:composer/phpoffice/phpspreadsheet","source":"GHSA-hrmw-qprp-wgmc"},{"ecosystem":"Packagist","fixed":["3.10.5"],"introduced":["3.3.0"],"last_affected":[],"package":"phpoffice/phpspreadsheet","purl":null,"source":"GHSA-hrmw-qprp-wgmc"},{"ecosystem":"Packagist","fixed":["3.10.5"],"introduced":["3.3.0"],"last_affected":[],"package":"phpoffice/phpspreadsheet","purl":"pkg:composer/phpoffice/phpspreadsheet","source":"GHSA-hrmw-qprp-wgmc"},{"ecosystem":"Packagist","fixed":["5.7.0"],"introduced":["4.0.0"],"last_affected":[],"package":"phpoffice/phpspreadsheet","purl":null,"source":"GHSA-hrmw-qprp-wgmc"},{"ecosystem":"Packagist","fixed":["5.7.0"],"introduced":["4.0.0"],"last_affected":[],"package":"phpoffice/phpspreadsheet","purl":"pkg:composer/phpoffice/phpspreadsheet","source":"GHSA-hrmw-qprp-wgmc"}],"prev":{"headline":"Devise: Open Redirect via Unvalidated `request.referrer` in Timeoutable Session Timeout Handler","id":"CVE-2026-40295"},"products":["PhpSpreadsheet"],"published":"2026-05-06","related":[{"cvss_score":9.2,"headline":"PhpSpreadsheet SSRF and RCE via PHP stream wrappers in IOFactory::load","id":"CVE-2026-34084","kev_date_added":null,"published":"2026-05-05"},{"cvss_score":8.8,"headline":"XML External Entity Reference (XXE) in PHPSpreadsheet","id":"CVE-2024-45048","kev_date_added":null,"published":"2024-08-28"},{"cvss_score":8.8,"headline":"XXE in PHPSpreadsheet due to incomplete fix for previous encoding issue","id":"CVE-2019-12331","kev_date_added":null,"published":"2019-11-07"},{"cvss_score":8.8,"headline":"XXE in PHPSpreadsheet due to encoding issue","id":"CVE-2018-19277","kev_date_added":null,"published":"2018-11-14"},{"cvss_score":8.3,"headline":"PhpSpreadsheet vulnerable to unauthorized reflected XSS in the constructor of the Downloader class","id":"CVE-2024-56365","kev_date_added":null,"published":"2025-01-03"},{"cvss_score":8.3,"headline":"PhpSpreadsheet vulnerable to unauthorized reflected XSS in the Accounting.php file","id":"CVE-2024-56366","kev_date_added":null,"published":"2025-01-03"},{"cvss_score":8.3,"headline":"PhpSpreadsheet allows unauthorized reflected XSS in `Convert-Online.php` file","id":"CVE-2024-56408","kev_date_added":null,"published":"2025-01-03"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-05-07","vendors":["PHPOffice"]},"summary":"Attackers can achieve stored XSS by crafting spreadsheet cells with specific custom number formats that bypass HTML escaping during conversion.","url":"https://insights.sbomify.com/CVE-2026-40296/"}