{"id":"CVE-2025-31699","kind":"vulnerability","aliases":["CVE-2025-31699"],"related":[],"title":"Apache Traffic Server: request smuggling lets attackers bypass access controls and poison cache","description":"Apache Traffic Server can return an origin connection to the shared pool while the origin is still waiting on a request body the client declared but never fully sent, including when the client used Expect: 100-continue. The origin then reads a later request on that connection as leftover body data, which lets an attacker smuggle requests past ATS access controls, disrupt other users' requests, or poison the cache.\n\n\n\nThis issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.15, from 10.0.0 through 10.1.4, 10.2.0.\n\n\n\nUsers are recommended to upgrade to version 9.2.16, 10.1.5, or 10.2.1, which fix the issue.","summary":"Apache Traffic Server can reuse an origin connection while the origin still waits for a request body, so the origin reads the next request as leftover data. An attacker can smuggle requests past ATS access controls, disrupt other users, or poison the cache.","severity":"critical","cvss":9.1,"epss":0.00266,"exploited":false,"exploited_at":null,"products":[{"name":"Apache Traffic Server","fixed":["9.2.16","10.1.5","10.2.1"],"affected":">= 8.0.0, <= 8.1.11; >= 9.0.0, <= 9.2.15; >= 10.0.0, <= 10.1.4; 10.2.0","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["apache-traffic-server","cache","request-smuggling","reverse-proxy","runtime","self-hosted"],"not_affected_if":["version-outside-affected-ranges"],"how_to_check":"Check the installed ATS version (for example with traffic_server -V or the package manager) and compare it to the affected ranges: 8.0.0 to 8.1.11, 9.0.0 to 9.2.15, 10.0.0 to 10.1.4, and 10.2.0.","fix":"Upgrade to 9.2.16, 10.1.5, or 10.2.1, depending on your release line.","status":"open","published_at":"2026-10-21T19:16:47+00:00","first_seen_at":"2026-10-23T21:57:29+00:00","triaged_at":"2026-10-23T22:32:58+00:00","updated_at":"2026-10-24T13:15:54+00:00","category":"runtime","confidence":0.8,"triage":{"at":"2026-10-23T22:32:58Z","model":"claude-haiku-5-5","output":{"fix":"Upgrade to 9.2.16, 10.1.5, or 10.2.1, depending on your release line.","reach":"internet","title":"Apache Traffic Server: request smuggling lets attackers bypass access controls and poison cache","impact":"high","summary":"Apache Traffic Server can reuse an origin connection while the origin still waits for a request body, so the origin reads the next request as leftover data. An attacker can smuggle requests past ATS access controls, disrupt other users, or poison the cache.","category":"runtime","who_cares":["apache-traffic-server","self-hosted","reverse-proxy"],"confidence":0.8,"needs_auth":"no","worst_case":"Attacker smuggles requests past access controls and poisons cache for other users","analyst_note":"","how_to_check":"Check the installed ATS version (for example with traffic_server -V or the package manager) and compare it to the affected ranges: 8.0.0 to 8.1.11, 9.0.0 to 9.2.15, 10.0.0 to 10.1.4, and 10.2.0.","needs_analyst":false,"not_affected_if":["version-outside-affected-ranges"],"user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"critical"},"cost_usd":0.000535,"input_tokens":3177,"output_tokens":435,"severity_before":"critical"},"analyst_status":"done","analyst_note":"Check the NVD and Apache ATS security advisory for the exact trigger conditions and any config workaround; the sources did not say whether a default configuration is exposed.","search":"'-2025':15A,18A '-31699':16A,19A '10.0.0':165C '10.1.4':167C '10.1.5':177C '10.2.0':168C '10.2.1':179C '100':116C '8.0.0':157C '8.1.11':159C '9.0.0':161C '9.2.15':163C '9.2.16':176C 'access':9A,72B,140C 'affect':152C 'apach':1A,24B,38B,81C,153C 'apache':20A 'apache-traffic-serv':23B 'at':71B,139C 'attack':7A,66B,135C 'bodi':54B,102C,130C 'bypass':8A 'cach':13A,27B,80B,149C 'client':104C,113C 'connect':45B,88C,127C 'continu':117C 'control':10A,73B,141C 'cve':14A,17A 'data':64B,131C 'declar':105C 'disrupt':74B,142C 'expect':115C 'fix':181C 'fulli':108C 'host':37B 'includ':110C 'issu':151C,183C 'later':123C 'leftov':63B,129C 'let':6A,133C 'never':107C 'next':60B 'origin':44B,48B,57B,87C,95C,119C 'past':70B,138C 'poison':12A,78B,147C 'pool':92C 'proxi':33B 'read':58B,121C 'recommend':171C 'request':4A,29B,53B,61B,69B,101C,124C,137C,145C 'request-smuggl':28B 'return':85C 'reus':42B 'revers':32B 'reverse-proxi':31B 'runtim':34B 'self':36B 'self-host':35B 'sent':109C 'server':3A,22A,26B,40B,83C,155C 'share':91C 'smuggl':5A,30B,68B,136C 'still':49B,97C 'traffic':2A,21A,25B,39B,82C,154C 'upgrad':173C 'use':114C 'user':76B,144C,169C 'version':175C 'wait':50B,98C","nicknames":[],"mitigations":[],"who_affected":null,"tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-21T19:16:47+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:L/SC:H/SI:H/SA:L/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":"security@apache.org","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2025-31699","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-31699","severity":null,"published_at":"2026-10-21T19:16:47+00:00","modified_at":"2026-10-23T12:18:04+00:00","first_seen_at":"2026-10-23T21:57:29+00:00","fetched_at":"2026-10-23T22:29:02+00:00","note":null},{"source":"analyst","external_id":"CVE-2025-31699:225","url":null,"severity":null,"published_at":"2026-10-23T22:27:22+00:00","modified_at":"2026-10-23T22:27:22+00:00","first_seen_at":"2026-10-23T22:27:22+00:00","fetched_at":"2026-10-23T22:27:22+00:00","note":"Affected/fixed versions confirmed from the Apache CNA text (via NVD, GHSA, Rapid7). I did not read the Apache mailing-list thread, so trigger conditions and any config workaround are unknown. No exploitation or public PoC found (not in KEV, EPSS under 1%). No community posts checked."},{"source":"epss","external_id":"CVE-2025-31699","url":"https://api.first.org/data/v1/epss?cve=CVE-2025-31699","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-24T13:15:54+00:00","fetched_at":"2026-10-24T13:15:54+00:00","note":null}],"documents":[{"id":1445,"url":"https://nvd.nist.gov/vuln/detail/CVE-2025-31699","title":"NVD CVE-2025-31699 (from Apache CNA)","kind":"advisory","source":"analyst","text":null,"published_at":null,"relation":"advisory","confidence":null,"note":null},{"id":1446,"url":"https://github.com/advisories/GHSA-4h97-h3mf-j6w7","title":"GHSA-4h97-h3mf-j6w7","kind":"advisory","source":"analyst","text":null,"published_at":null,"relation":"describes","confidence":null,"note":null},{"id":1448,"url":"https://www.rapid7.com/db/vulnerabilities/cve-2025-31699/","title":"Rapid7 CVE-2025-31699","kind":"other","source":"analyst","text":null,"published_at":null,"relation":"mentions","confidence":null,"note":null}],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}