{"id":"CVE-2026-115473","kind":"vulnerability","aliases":["CVE-2026-115473"],"related":[],"title":"Mongoose: short-path check reads one byte past buffer, exposing adjacent memory","description":"Mongoose is an embedded web server and network library. Prior to 7.22, mg_path_is_sane in src/util.c read path.buf[1] without first requiring path.len to be at least two and read s[2] when only two bytes remained. Unauthenticated remote requests reaching mg_http_upload or mg_http_serve_dir with the affected short path shapes could therefore trigger one-byte heap out-of-bounds reads. On bare-metal or RTOS targets without memory protection, the adjacent byte could be exposed or influence whether a path was accepted, and instrumented builds could crash. This issue is fixed in version 7.22.","summary":"Mongoose's path sanity check reads one byte beyond a short request path, which can leak an adjacent heap byte or crash instrumented builds. An unauthenticated remote request reaching the upload or static-serve handlers with a very short path can trigger it.","severity":"medium","cvss":6.5,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["bare-metal","embedded","http-server","mongoose","package","rtos"],"not_affected_if":["handlers-unused","no-network-exposure"],"how_to_check":"- Check the Mongoose version in your project, e.g. `grep -i mongoose_version mongoose.h` or the vendored copy's header.\n- Confirm whether `mg_http_upload` or `mg_http_serve_dir` is reachable from untrusted network requests.","fix":"- Mongoose: move to `7.22` or later.","status":"open","published_at":"2026-11-04T22:17:50+00:00","first_seen_at":"2026-11-04T23:08:47+00:00","triaged_at":"2026-11-04T23:10:04+00:00","updated_at":"2026-11-04T23:10:04+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-11-04T23:10:04Z","model":"claude-haiku-5-5","output":{"fix":"- Mongoose: move to `7.22` or later.","reach":"internet","title":"Mongoose: short-path check reads one byte past buffer, exposing adjacent memory","impact":"low","summary":"Mongoose's path sanity check reads one byte beyond a short request path, which can leak an adjacent heap byte or crash instrumented builds. An unauthenticated remote request reaching the upload or static-serve handlers with a very short path can trigger it.","audience":"developers","category":"package","nicknames":[],"who_cares":["mongoose","embedded","rtos","bare-metal","http-server"],"confidence":0.7,"fix_status":"available","needs_auth":"no","worst_case":"adjacent heap byte exposed or request path acceptance altered","analyst_note":"","how_to_check":"- Check the Mongoose version in your project, e.g. `grep -i mongoose_version mongoose.h` or the vendored copy's header.\n- Confirm whether `mg_http_upload` or `mg_http_serve_dir` is reachable from untrusted network requests.","plain_action":"","needs_analyst":false,"not_affected_if":["no-network-exposure","handlers-unused"],"who_is_affected":"Teams that embed Mongoose in a device or service and serve HTTP requests from untrusted clients through mg_http_upload or mg_http_serve_dir. The issue is worst on bare-metal or RTOS targets without memory protection; systems with no network-facing use of those handlers can skip it.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"medium"},"cost_usd":0.00071,"input_tokens":4353,"output_tokens":550,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-115473':16A,19A '-2026':15A,18A '1':93C '2':106C '7.22':84C,176C 'accept':164C 'adjac':12A,47B,153C 'affect':126C 'bare':21B,144C 'bare-met':20B,143C 'beyond':38B 'bound':140C 'buffer':10A 'build':53B,167C 'byte':8A,37B,49B,110C,135C,154C 'check':5A,34B 'could':130C,155C,168C 'crash':51B,169C 'cve':14A,17A 'dir':123C 'embed':23B,76C 'expos':11A,157C 'first':95C 'fix':173C 'handler':65B 'heap':48B,136C 'http':25B,117C,121C 'http-server':24B 'influenc':159C 'instrument':52B,166C 'issu':171C 'leak':45B 'least':101C 'librari':81C 'memori':13A,150C 'metal':22B,145C 'mg':85C,116C,120C 'mongoos':1A,27B,30B,73C 'network':80C 'one':7A,36B,134C 'one-byt':133C 'out-of-bound':137C 'packag':28B 'past':9A 'path':4A,32B,42B,70B,86C,128C,162C 'path.buf':92C 'path.len':97C 'prior':82C 'protect':151C 'reach':58B,115C 'read':6A,35B,91C,104C,141C 'remain':111C 'remot':56B,113C 'request':41B,57B,114C 'requir':96C 'rtos':29B,147C 'sane':88C 'saniti':33B 'serv':64B,122C 'server':26B,78C 'shape':129C 'short':3A,40B,69B,127C 'short-path':2A 'src/util.c':90C 'static':63B 'static-serv':62B 'target':148C 'therefor':131C 'trigger':72B,132C 'two':102C,109C 'unauthent':55B,112C 'upload':60B,118C 'version':175C 'web':77C 'whether':160C 'without':94C,149C","nicknames":[],"mitigations":[],"who_affected":"Teams that embed Mongoose in a device or service and serve HTTP requests from untrusted clients through mg_http_upload or mg_http_serve_dir. The issue is worst on bare-metal or RTOS targets without memory protection; systems with no network-facing use of those handlers can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"developers","plain_action":null,"pkeys":[],"ptokens":[],"labels":["baremetal","embedded","httpserver","medium","mongoose","package","rtos"],"campaign_type":null,"first_public_at":"2026-10-23T13:52:08+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L","cvss_by":"security-advisories@github.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-115473","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-115473","severity":null,"published_at":"2026-11-04T22:17:50+00:00","modified_at":"2026-11-04T22:17:50+00:00","first_seen_at":"2026-11-04T23:08:47+00:00","fetched_at":"2026-11-04T23:08:47+00:00","note":null}],"documents":[{"id":71125,"url":"https://github.com/cesanta/mongoose/commit/b55de8b151d1466a3e41d1f854f22eeb6faa23dc","title":"Patch: github.com","kind":"other","source":"nvd","publisher":"vendor","text":null,"published_at":null,"relation":"fix","confidence":null,"note":"Patch: github.com"},{"id":71126,"url":"https://github.com/cesanta/mongoose/releases/tag/7.22","title":"Release notes: github.com","kind":"release","source":"nvd","publisher":"vendor","text":null,"published_at":null,"relation":"fix","confidence":null,"note":"Release notes: github.com"},{"id":71127,"url":"https://github.com/cesanta/mongoose/security/advisories/GHSA-cjmx-764f-286c","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-10-23T13:52:08+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"}],"exploit_sources":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}