{"id":"CVE-2026-121443","kind":"vulnerability","aliases":["CVE-2026-121443"],"related":[],"title":"svg-sanitizer: truncated SVG input crashes requests with an uncaught error","description":"svg-sanitizer from 1.1.0 before 1.1.1 contains a denial of service vulnerability that allows remote attackers to crash requests by submitting SVG input ending inside an unclosed tag. Attackers can upload truncated input like a single '<' to trigger an uncaught ValueError from strpos() in hasElementWithTooManyAttributes() or hasInternalDtdSubset() on PHP 8, failing the request.","summary":"svg-sanitizer versions from 1.1.0 before 1.1.1 throw an uncaught ValueError when given SVG input that ends inside an unclosed tag, such as a single '<'. An attacker who can submit such input makes the request fail, which is a denial of service.","severity":"medium","cvss":6.9,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["composer","package","php","svg-upload"],"not_affected_if":["no-untrusted-svg","versions-outside-range"],"how_to_check":"- Check the installed version with `composer show enshrined/svg-sanitizer` (package name unknown from sources; verify it)\n- Search your dependency lock file for `svg-sanitizer` at a version below `1.1.1`\n- Find code paths that pass user-uploaded SVG files to the sanitizer","fix":"- `svg-sanitizer` `1.1.1` (fixed version from the sources; earlier versions from `1.1.0` are affected)","status":"open","published_at":"2026-11-03T15:17:36+00:00","first_seen_at":"2026-11-03T15:22:00+00:00","triaged_at":"2026-11-03T15:23:11+00:00","updated_at":"2026-11-03T15:23:11+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-11-03T15:23:11Z","model":"claude-haiku-5-5","output":{"fix":"- `svg-sanitizer` `1.1.1` (fixed version from the sources; earlier versions from `1.1.0` are affected)","reach":"internet","title":"svg-sanitizer: truncated SVG input crashes requests with an uncaught error","impact":"low","summary":"svg-sanitizer versions from 1.1.0 before 1.1.1 throw an uncaught ValueError when given SVG input that ends inside an unclosed tag, such as a single '<'. An attacker who can submit such input makes the request fail, which is a denial of service.","audience":"developers","category":"package","nicknames":[],"who_cares":["php","svg-upload","composer"],"confidence":0.7,"fix_status":"available","needs_auth":"no","worst_case":"Requests fail with an uncaught error; repeated attempts cause sustained denial of service","analyst_note":"","how_to_check":"- Check the installed version with `composer show enshrined/svg-sanitizer` (package name unknown from sources; verify it)\n- Search your dependency lock file for `svg-sanitizer` at a version below `1.1.1`\n- Find code paths that pass user-uploaded SVG files to the sanitizer","plain_action":"","needs_analyst":false,"not_affected_if":["no-untrusted-svg","versions-outside-range"],"who_is_affected":"Applications that accept user-supplied SVG uploads or input and run them through svg-sanitizer on PHP 8 are exposed. Systems that never pass untrusted SVG to the library can skip it. The sources do not say whether the package is only used on PHP 8 in every case, only that the failing functions are reached on PHP 8.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000725,"input_tokens":4218,"output_tokens":606,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-121443':15A,18A '-2026':14A,17A '1.1.0':30B,72C '1.1.1':32B,74C '8':118C 'allow':82C 'attack':52B,84C,97C 'compos':19B 'contain':75C 'crash':7A,86C 'cve':13A,16A 'denial':65B,77C 'end':42B,92C 'error':12A 'fail':61B,119C 'given':38B 'haselementwithtoomanyattribut':113C 'hasinternaldtdsubset':115C 'input':6A,40B,57B,91C,101C 'insid':43B,93C 'like':102C 'make':58B 'packag':20B 'php':21B,117C 'remot':83C 'request':8A,60B,87C,121C 'sanit':3A,27B,70C 'servic':67B,79C 'singl':50B,104C 'strpos':111C 'submit':55B,89C 'svg':2A,5A,23B,26B,39B,69C,90C 'svg-sanit':1A,25B,68C 'svg-upload':22B 'tag':46B,96C 'throw':33B 'trigger':106C 'truncat':4A,100C 'uncaught':11A,35B,108C 'unclos':45B,95C 'upload':24B,99C 'valueerror':36B,109C 'version':28B 'vulner':80C","nicknames":[],"mitigations":[],"who_affected":"Applications that accept user-supplied SVG uploads or input and run them through svg-sanitizer on PHP 8 are exposed. Systems that never pass untrusted SVG to the library can skip it. The sources do not say whether the package is only used on PHP 8 in every case, only that the failing functions are reached on PHP 8.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"developers","plain_action":null,"pkeys":[],"ptokens":[],"labels":["composer","medium","package","php","svgupload"],"first_public_at":"2026-10-20T09:46:26+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/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":"disclosure@vulncheck.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-121443","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121443","severity":null,"published_at":"2026-11-03T15:17:36+00:00","modified_at":"2026-11-03T15:17:36+00:00","first_seen_at":"2026-11-03T15:22:00+00:00","fetched_at":"2026-11-03T15:22:00+00:00","note":null}],"documents":[{"id":58413,"url":"https://github.com/darylldoyle/svg-sanitizer/security/advisories/GHSA-f7cw-vfxq-7ph2","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-10-20T09:46:26+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"},{"id":58414,"url":"https://www.vulncheck.com/advisories/svg-sanitizer-from-1.1.0-before-1.1.1-denial-of-service-via-unclosed-tag","title":"Third-party advisory: www.vulncheck.com","kind":"advisory","source":"nvd","publisher":"research","text":null,"published_at":null,"relation":"advisory","confidence":null,"note":"Third-party advisory: www.vulncheck.com"}],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}