{"id":"CVE-2026-111442","kind":"vulnerability","aliases":["CVE-2026-111442"],"related":[],"title":"Backdrop CMS: uploaded SVG files can run scripts when viewed directly","description":"Backdrop CMS Core 1.35.x before 1.35.2 and 1.34.x before 1.34.6 does not sufficiently validate uploaded SVG images to ensure they lack potentially dangerous SVG tags. SVG images can contain clickable links or executable scripting. By uploading a crafted SVG, it is possible to execute scripting in the browser when an SVG image is viewed. This issue is mitigated by the attacker needing to be able to upload SVG images, and that Backdrop embeds all uploaded SVG images within <img> tags, which prevents script from executing. The SVG must be viewed directly by its URL in order to run any embedded scripting.","summary":"Backdrop CMS Core does not sufficiently filter dangerous tags from uploaded SVG images, so a crafted SVG can carry script. The script runs in a visitor's browser only when the SVG is opened directly by its URL, since Backdrop normally embeds uploads in img tags, which blocks scripts.","severity":"medium","cvss":5.3,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["backdrop-cms","php","runtime","self-hosted"],"not_affected_if":["no-svg-uploads","other-version-lines"],"how_to_check":"- Check the installed Backdrop CMS Core version with `unknown` (the sources do not give a command)\n- Look for uploaded `.svg` files in the site's files directory and check whether they are served directly by URL","fix":"- Upgrade Backdrop CMS Core 1.35.x to `1.35.2` or later\n- Upgrade Backdrop CMS Core 1.34.x to `1.34.6` or later","status":"open","published_at":"2026-10-16T04:18:29+00:00","first_seen_at":"2026-10-23T21:57:12+00:00","triaged_at":"2026-10-25T04:28:41+00:00","updated_at":"2026-10-25T04:28:41+00:00","category":"runtime","confidence":0.7,"triage":{"at":"2026-10-25T04:28:41Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade Backdrop CMS Core 1.35.x to `1.35.2` or later\n- Upgrade Backdrop CMS Core 1.34.x to `1.34.6` or later","reach":"internet","title":"Backdrop CMS: uploaded SVG files can run scripts when viewed directly","impact":"medium","summary":"Backdrop CMS Core does not sufficiently filter dangerous tags from uploaded SVG images, so a crafted SVG can carry script. The script runs in a visitor's browser only when the SVG is opened directly by its URL, since Backdrop normally embeds uploads in img tags, which blocks scripts.","category":"runtime","nicknames":[],"who_cares":["backdrop-cms","php","self-hosted"],"confidence":0.7,"needs_auth":"yes","worst_case":"Script runs in a visitor's browser on the CMS domain","analyst_note":"","how_to_check":"- Check the installed Backdrop CMS Core version with `unknown` (the sources do not give a command)\n- Look for uploaded `.svg` files in the site's files directory and check whether they are served directly by URL","needs_analyst":false,"not_affected_if":["no-svg-uploads","other-version-lines"],"who_is_affected":"Sites running Backdrop CMS Core 1.35.x before 1.35.2 or 1.34.x before 1.34.6 that allow users to upload SVG images. Exposure depends on an attacker being able to upload SVGs and on someone opening the file's URL directly. Sites that do not accept SVG uploads, or that are on other release lines, can skip it.","user_interaction":"yes","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000644,"input_tokens":3456,"output_tokens":596,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-111442':14A,17A '-2026':13A,16A '1.34':83C '1.34.6':86C '1.35':78C '1.35.2':81C 'abl':141C 'attack':137C 'backdrop':1A,19B,26B,65B,75C,148C 'backdrop-cm':18B 'block':73B 'browser':53B,124C 'carri':44B 'clickabl':106C 'cms':2A,20B,27B,76C 'contain':105C 'core':28B,77C 'craft':41B,114C 'cve':12A,15A 'danger':33B,99C 'direct':11A,60B,166C 'emb':67B,149C 'embed':175C 'ensur':95C 'execut':109C,120C,160C 'file':5A 'filter':32B 'host':25B 'imag':38B,93C,103C,128C,145C,153C 'img':70B 'issu':132C 'lack':97C 'link':107C 'mitig':134C 'must':163C 'need':138C 'normal':66B 'open':59B 'order':171C 'php':21B 'possibl':118C 'potenti':98C 'prevent':157C 'run':7A,48B,173C 'runtim':22B 'script':8A,45B,47B,74B,110C,121C,158C,176C 'self':24B 'self-host':23B 'sinc':64B 'suffici':31B,89C 'svg':4A,37B,42B,57B,92C,100C,102C,115C,127C,144C,152C,162C 'tag':34B,71B,101C,155C 'upload':3A,36B,68B,91C,112C,143C,151C 'url':63B,169C 'valid':90C 'view':10A,130C,165C 'visitor':51B 'within':154C 'x':79C,84C","nicknames":[],"mitigations":[],"who_affected":"Sites running Backdrop CMS Core 1.35.x before 1.35.2 or 1.34.x before 1.34.6 that allow users to upload SVG images. Exposure depends on an attacker being able to upload SVGs and on someone opening the file's URL directly. Sites that do not accept SVG uploads, or that are on other release lines, can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-16T04:18:29+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","cvss_by":"cve@mitre.org","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-111442","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-111442","severity":null,"published_at":"2026-10-16T04:18:29+00:00","modified_at":"2026-10-21T03:17:18+00:00","first_seen_at":"2026-10-23T21:57:12+00:00","fetched_at":"2026-10-23T22:28:54+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}