{"id":"CVE-2026-104774","kind":"vulnerability","aliases":["CVE-2026-104774","GHSA-pc5q-qfxp-ggqv","GO-2026-6696"],"related":[],"title":"Coraza: jsDecode Off-by-One in Octal Escape Handling Enables WAF Bypass in github.com/corazawaf/coraza","description":"OWASP Coraza WAF is a golang modsecurity compatible web application firewall library. From 3.0.0 until 3.8.0, the t:jsDecode transformation in internal/transformations/js_decode.go:64-70 includes the backslash in the octal buffer, causing ParseInt to fail and return a null byte. The flaw is triggered when a rule relies on t:jsDecode and the request contains JavaScript octal escape sequences. An unauthenticated attacker can encode attack syntax with JavaScript octal escapes so the backend decodes the intended bytes while Coraza rules using t:jsDecode inspect corrupted null-byte output. The mismatch can bypass WAF rules and expose the protected application to attacks such as cross-site scripting or SQL injection. This issue is fixed in version 3.8.0.","summary":"Coraza, a Go web application firewall library, mishandles JavaScript octal escapes in its t:jsDecode transform, decoding them into null bytes. An unauthenticated attacker can hide XSS or SQL injection payloads in octal escapes so the WAF rules miss them while the backend still decodes the attack.","severity":"medium","cvss":5.8,"epss":0.004,"exploited":false,"exploited_at":null,"products":[{"name":"github.com/corazawaf/coraza","fixed":[],"affected":"all versions","ecosystem":"go"},{"name":"github.com/corazawaf/coraza/v2","fixed":[],"affected":"all versions","ecosystem":"go"},{"name":"github.com/corazawaf/coraza/v3","fixed":["3.8.0"],"affected":">= 3.0.0, < 3.8.0","ecosystem":"go"}],"ecosystems":["go"],"tags":["coraza","go","modsecurity","package","waf"],"not_affected_if":["no-jsdecode-rules","version-3.8.0-or-later"],"how_to_check":"Run go list -m github.com/corazawaf/coraza/v3 in the project and check whether the version is >= 3.0.0 and < 3.8.0.\nCheck whether any WAF rule uses t:jsDecode.","fix":"Upgrade github.com/corazawaf/coraza/v3 to 3.8.0 or later.","status":"open","published_at":"2026-10-12T20:17:07+00:00","first_seen_at":"2026-10-23T19:13:08+00:00","triaged_at":"2026-10-23T19:58:06+00:00","updated_at":"2026-10-23T19:58:06+00:00","category":"package","confidence":0.8,"triage":{"at":"2026-10-23T19:58:06Z","model":"claude-haiku-5-5","output":{"fix":"Upgrade github.com/corazawaf/coraza/v3 to 3.8.0 or later.\nunknown","summary":"Coraza, a Go web application firewall library, mishandles JavaScript octal escapes in its t:jsDecode transform, decoding them into null bytes. An unauthenticated attacker can hide XSS or SQL injection payloads in octal escapes so the WAF rules miss them while the backend still decodes the attack.","category":"package","who_cares":["go","coraza","waf","modsecurity"],"confidence":0.8,"analyst_note":"","how_to_check":"Run go list -m github.com/corazawaf/coraza/v3 in the project and check whether the version is >= 3.0.0 and < 3.8.0.\nCheck whether any WAF rule uses t:jsDecode.\nunknown","needs_analyst":false,"not_affected_if":["version-3.8.0-or-later","no-jsdecode-rules"],"severity_if_unknown":"medium"},"cost_usd":0.000412,"input_tokens":2404,"output_tokens":344,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-104774':20A,31A '-2026':19A,27A,30A '-6696':28A '-70':116C '/corazawaf/coraza':17A,34A '/corazawaf/coraza/v2':37A '/corazawaf/coraza/v3':40A '3.0.0':106C '3.8.0':108C,210C '64':115C 'applic':50B,102C,192C 'attack':69B,92B,154C,157C,194C 'backend':88B,165C 'backslash':119C 'buffer':123C 'bypass':13A,185C 'byte':66B,132C,169C,180C 'caus':124C 'compat':100C 'contain':147C 'coraza':1A,41B,46B,94C,171C 'corrupt':177C 'cross':198C 'cross-sit':197C 'cve':18A,29A 'decod':62B,90B,166C 'enabl':11A 'encod':156C 'escap':9A,56B,79B,150C,162C 'expos':189C 'fail':127C 'firewal':51B,103C 'fix':207C 'flaw':134C 'ggqv':25A 'ghsa':22A 'ghsa-pc5q-qfxp-ggqv':21A 'github.com':16A,33A,36A,39A 'github.com/corazawaf/coraza':15A,32A 'github.com/corazawaf/coraza/v2':35A 'github.com/corazawaf/coraza/v3':38A 'go':26A,42B,48B 'golang':98C 'handl':10A 'hide':71B 'includ':117C 'inject':75B,203C 'inspect':176C 'intend':168C 'internal/transformations/js_decode.go':114C 'issu':205C 'javascript':54B,148C,160C 'jsdecod':2A,60B,111C,143C,175C 'librari':52B,104C 'mishandl':53B 'mismatch':183C 'miss':84B 'modsecur':43B,99C 'null':65B,131C,179C 'null-byt':178C 'octal':8A,55B,78B,122C,149C,161C 'off-by-on':3A 'one':6A 'output':181C 'owasp':93C 'packag':44B 'parseint':125C 'payload':76B 'pc5q':23A 'protect':191C 'qfxp':24A 'reli':140C 'request':146C 'return':129C 'rule':83B,139C,172C,187C 'script':200C 'sequenc':151C 'site':199C 'sql':74B,202C 'still':89B 'syntax':158C 'transform':61B,112C 'trigger':136C 'unauthent':68B,153C 'use':173C 'version':209C 'waf':12A,45B,82B,95C,186C 'web':49B,101C 'xss':72B","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-12T20:17:07+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N","cvss_by":"security-advisories@github.com","poc_count":0,"sources":[{"source":"govuln","external_id":"GO-2026-6696","url":"https://pkg.go.dev/vuln/GO-2026-6696","severity":null,"published_at":"2026-10-19T21:08:17+00:00","modified_at":"2026-10-19T21:08:17+00:00","first_seen_at":"2026-10-23T19:13:08+00:00","fetched_at":"2026-10-23T19:13:08+00:00","note":null},{"source":"epss","external_id":"CVE-2026-104774","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-104774","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-23T19:13:43+00:00","fetched_at":"2026-10-23T19:13:43+00:00","note":null},{"source":"nvd","external_id":"CVE-2026-104774","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-104774","severity":null,"published_at":"2026-10-12T20:17:07+00:00","modified_at":"2026-10-16T20:04:29+00:00","first_seen_at":"2026-10-23T19:35:23+00:00","fetched_at":"2026-10-23T19:35:23+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"}